Since you mentioned you went to a school already (and assuming you meant some kind of post-secondary school); I do think it’s outrageous that some schools limit full library access to only the time one is completing their studies. Lots of former students would benefit and since anyone with access through their employers is likely using the employer’s library access, I can’t imagine former students would significantly increase the cost of maintaining database access…

I got lucky and still have access through the alumni association at my uni, but I don’t believe that’s true at all schools.

depends a bit on the text book and library, but yes. that’s kind of the point of university libraries (which you normally can also visit, as far as I am aware)

In fact, I just checked: my local uni library will give you a membership card for only a handful of bucks a year

Not my cancer research niche textbooks.