The reason why this has to be the case in terms of brokerage accounting is that there are different ways to account for your purchases and sales of securities that can result in different levels of tax. Brokerages usually allow you to choose one on your 1099-B if you want (despite the fact that this may be hidden). You are only allowed to use one accounting method across all of your accounts. If you only have one brokerage account, they can make the tax-minimizing choice for you automatically, but if not, you have to make sure they use the same method.
Certainly stock grants end up as W-2 income, but unless you automatically sell all of them, your choice of accounting methods matters. Many people I know have at least 2, one for employment-related stock and the other for their own trading. You don't even need options to get an accounting problem.
Also, I think you have a very narrow view of who actually cares about special tax circumstances. Teachers have several special credits. So do students. So do people who save for retirement. Not to mention people who run a small business or a side hustle. This isn't a 10% situation, this is more like 30-50% in any given year, and almost nobody files a bog-standard return every year for their entire life.
It would be nice, however, if the IRS told you about all of the W-2s and 1099s they got before you had to file your taxes. The good news is that you can do this if you file for an extension on your taxes and check an obscure section of the IRS website - many accountants do it.