Is it just me, or was shared caching not on its way out already? I mean, it was great when every website had jQuery on it, but with the proliferation of new JavaScript libraries, the chance of getting a shared cache hit must be getting smaller.

Besides, Webpack and similar bundlers with tree-shaking abilities makes it practical to just load a subset of a large library.

And last (but certainly not least) there is the security angle. Imagine if someone managed to sneak malicious code on to CDNJS or Bootstrap CDN, how many nasty things they might be able to get up to, even if everyone remembered to set crossorigin="anonymous" on their shared assets.