You're confusing being neurodivergent with some aspects of increased cognitive function. There are plenty of nondivergent people with increased cognitive function, and plenty of neurodivergent people with normal or impared cognitive function (though the distribution is wider).
So some of your questions don't make any sense.
A few people do act like it hurts to think, but mostly people do not, and some neurotypical people think an immense amount.
It's nice to have a sufficient awareness of other people's likely cognitive states so that one can ask a simple question and almost surely get an answer. A lot of neurodivergent people focus on such different aspects of the question (or fail to give the expected context) that it's hard to figure out what they’re getting at. For instance, in one physics class I took there was an obviously neurodivergent student who solved almost all the problems correctly, but whose explanations for what they were doing made no sense at all to anyone else, including me--everything would be some tangent, almost wholly unrelated to how the material was taught or the relevant information for that problem.
When communicating, the question is always "what does the other person know and how do I get them from that state to the state where they also know this thing I want them to know." Neurotypicals have a much easier go of it because, well...that's kind of what typical means, no? Alike? So it's easy to guess.
Some neurotypicals are very attuned to meeting expectations. This is, absolutely, an area where the divergence is very often in one direction: away from conformance. Some people do indeed know the names of fashion designers and what's "so cute"; others just have a general sense of "looks good" or "nah". In general, it's used as a way to communicate social standing and social awareness. The overall utility is quite dubious--while being aware enough to set some sort of general expectation about what people can expect for you is good (because there are a variety of different ways in which people can act and it is nice to have a heads-up), that you didn't get the memo that green hair scrunchies are so 2021 is not the kind of thing that seems to correlate with anything remotely useful. You get the magazines if you like this stuff and think it's fun to see what people are wearing. You know what's in or out of fashion because you see what people are wearing, especially the high-status people who aren't so high-status that you couldn't seek to emulate them, and you can formulate subconscious rules that generate a more compact representation of what those people wear than just a list of what they happened to wear on any particular day, and you can read off your own set of rules to pick your own outfits. If your ruleset isn't a good match, your friends will know and will say polite-sounding things that are coded for "that doesn't work", which you can pick up on, if you're sufficiently attuned, because you understand how body language and facial expressions and amount of follow-up and so on are correlated to genuine enthusiasm as compared to politeness. Because this is all rather subjective and fuzzy, if you mess up a few times it's no big deal. If you start constantly messing up, your social standing will drop among people who really care about fashion.
Note that even people who don't really care about fashion a lot, but who are slightly aware, still develop subconscious models of what is “in”, so they often can recognize when someone is really with it.
Because we're a highly social species, being very attuned to social cues is a legitimately useful indicator of higher standing--it's useful. Just like being strong is, if strength might be needed.
A $100+ haircut is on average distinguishable from a $20 Supercuts cut. Firstly, a lot of the $100+ haircuts are not just haircuts: there might be some straightening or curling or perming or bleaching or whatever. But let's say, no, it's really just cutting. $100+ haircuts more reliably look good (not perfect, but the chance of really not looking good is much lower than at Supercuts), are more likely to mimic a particular style if that's what you want, and usually are technically superior (e.g. more care taken when thinning, better symmetry or more asthetically pleasing broken symmetry). And, for $100, you're probably seeing the same stylist repeatedly, so they probably know the quirks of your hair and are taking those quirks into account (cut when wet, but they know that on the left side your hair bounces up a half-inch higher than on the right, so they cut the wet hair unevenly such that when it dries it's even). Furthermore, with appropriate styling products they can make your hair look great right away--you can go out on a date (with someone who cares about appearance)--and it will still look good after a washing. (Different, but good.)
Now, is all that worth it? Probably not. Then again, if your only goal is for it to be short and out of your face, a pair of decent haircutting scissors is $10--buy them and do it yourself. Supercuts isn't worth it either, unless you kinda care about the outcome! But Supercuts vs. higher-end professional stylist absolutely a case where the 80/20 rule applies: you get 80% of the benefit for 20% of the price. (Literally.)
Neurotypicals absolutely notice the $4000 line item. If it's spent on them, they'll definitely notice the improved service. If not, they might wonder if it was really called for. Those who go on trips will tend to feel that the in-person trip was worth it. If you check objectively after the fact, the feeling may well be wrong: the business outcome would have been the same. But it will feel like it was worth it because, well, social animal, making social connection. Even if it wasn't useful this time, in general, it is. People respond differently to people with whom they have a connection. It can matter.
Hearing conversations in a loud room is a matter of subconscious information processing in the auditory cortex. You cannot train it very much (especially as an adult). Some neurotypicals are great at it. Some are awful, and those who are awful tend to avoid the situation.
People don't believe the Facebook news stream, but they believe "their people". There's a very strong bias for neurotypicals to believe and give every benefit of the doubt to "their tribe", however their tribe happens to get defined. It can get defined in minutes simply by making an arbitrary distinction and establishing a competition. ("Green against purple! You're green! Go!"--at this point, everyone labeled green will give extra benefit of the doubt to anyone else labeled green and be extra critical of anyone labeled purple.)
Super handy reflex for coalition-building. Super un-handy reflex for getting anything right, however. Instant bias generation is built in.
Whether people debate with their doctor is largely orthogonal--doctors aren't usually either "my tribe" or "the enemy tribe" (except when it comes to Covid vaccines).
Neurotypicals also get annoyed with phone menus. But they have high enough tolerance to put up with it. It's not excruciating, just ugh.
Neurodivergent people often emit social miscues at such a dramatic rate that, yes, neurotypicals can pick out that something is wrong pretty quickly. Narcissists do tend to find ways to mask their motives and train their tactics against neurotypicals, so it's unsurprising that it works best against neurotypicals (I seem to remember some studies to this effect).