Most libraries have already fallen pretty far from their original mission. A lot of them are primarily free movie/video game rental facilities that also provide a place to use a computer and get on the Internet. The book-side is almost secondary now, and tends to have a massive recency bias combined with a general predilection for romance, mystery, and political novels.
Older books, even classics, even very rare books, are being "removed" from collections, almost always a euphemism for "destroyed." For example, in my large multi-county library system, there are a single digit number, total, of all the works of ancient Greece and Rome. Even the ILL network has a lot of holes in it. This was not the case a few decades ago - the library is how I was accidentally exposed to them and acquired a lifelong interest in ancient history. There are more copies of a single example of the hyped-up forgettable ideological fare that gets churned out and forgotten on an annual basis.
Typically when I bring this up, people tell me that it's all available online anyway. Sure, big-name classical works are. A lot of niche books (on narrow technical or scientific subjects, or local history, for example) are being lost forever. And accidental exposure to physical copies of books is a huge and important method of discovery.
So to be honest, I don't think libraries can get any worse. I honestly don't think most people understand the scale of the destruction going on right now.