Just because business folks don't know how to value certain developer practices doesn't let you off the hook. Just do what you have to do and if it takes longer because you had to learn how to do it, then it takes longer.
Let the business folks tell you when it's taking too long to deliver features.
A manager looks at a programmer bringing up something like unit testing as "why the fuck is he asking me about this, it's his job? Obviously because he's asking me it's outside of his professional ken, so that means it's going to take absolutely forever." Out loud he'll just say, "Can you just get the feature done?"
Don't ask, just do it. It takes as long as it takes. If they ask, just say it's not done yet.
But for what it's worth, I agree with you in that I'm still on the hook. Either to help educate my manager, or to pick managers who already understand this stuff.
All they care about is that the code works, and that features can be delivered on time.
That second part "delivered on time" includes maintaining the comments along with the code since it makes the code more readable, and eases future changes. If Management doesn't give you time to write maintainable code (which includes keeping comments in sync with the code), then you may as well start looking for a new job because the technical debt is going to pile up and it's going to get harder and harder to meet deadlines.