As someone that is self-employed, and gets to pay that otherwise invisible bit I mentioned earlier myself... do I know about it? yes (I did as a hiring manager back in the day, too); do I think about it? yes... but there's an extra "implied" tax here because my time doing tax prep related work is also a cost in addition to the taxes.

So I now get to spend hours that I could otherwise be productive with, or spend on leisure activities, on the problem of understanding what is being taken from me. As I said, I agree with you that people should be conscious of what is taken from them. People should make conscious informed decisions in many, many areas of their life. But to take that half their earnings and then insist that they spend hours of their own time (true even if they hire tax preparation services) just to be sure they don't lose more than they're legally required to is kinda rubbing salt in the wound isn't it? Of course you could hire accountants to deal with those issues, but now you're just changing that cost in time to cost in money.