It really depends on where you work. In large companies, there was already a strong emphasis on accessibility 10-15 years ago, if only because there's a bunch of requirements if you want to sell software to the government.
As for small and simple libraries... it's great when the subject matter is also small and simple. UI is not, though.
As for small and simple libraries... it's great when the subject matter is also small and simple. UI is not, though.