You misunderstand my argument but I'm not sure which part of it is confusing.
You seem to be arguing that library book bans are innocuous, because one can simply find the books elsewhere.
Is that correct?
That does not argue for shutting down libraries. It doesn't make an argument for what to do with libraries at all.
Have we?
The costs to doing so have certainly gone down, but the entire de facto system is much more centralized than its physical-based precursor was.
Once a physical book was created, it existed until it was destroyed.
In contrast, all digital destruction takes is a takedown notice to the centralized host and ambivalence on the part of anyone else having archived it.
Physical books were persistent by default.