Yes, but sites like: https://github.com/iamadamdev/bypass-paywalls-chrome https://sci-hub.tw/ exist and make it trivial to get around draconian publishing practices. I'm not advocating not paying for journalism---it's just that not everyone realistically can, and paywalling them seems like a bad solution.

A more plausible reason, at least to me, is the increasing specialization of fields and lack of cross-field communication.

Also, ideas seem to be flowing plentifully at least in math and TCS, where old and hard conjectures are still being proved with astonishing regularity.

You're being clever.... except this shows you didn't both to even read the abstract.