Doing crazy things with CSS, including animations, has never been easier or more consistent between browsers, and yet creativity in web design has gone down practically to zero these days. I blame mobile, where nobody can seem to escape from the "responsive column of blandly styled content" paradigm.
My theory for why this is is that in the past when the web was arcane and challenging to learn to develop, this actually acted as a filter for people who had a special sort of intellectual curiosity and passion to really push through and make what they wanted to make. It’s great now that the web is so broadly accessible, but now no such filter exists, so truly creative sites are fewer and further between.
If anything, web development is far more arcane and challenging now. No one just writes HTML, CSS or JS in a text editor anymore, the bare minimum expectation is to use complex frontend frameworks and NPM and compile everything from other languages. Compared to the sprawling, byzantine nightmare of modern web development, JQuery plugins were a breeze.
I think, it's simply the case that the web has matured, and more people are concerned with content than the superficiality of quirky presentation nowadays. Just as it's possible for an author to publish a book without knowing typesetting or running their own press, one can publish to the internet without knowing even the basics of HTML, CSS or JS.
And of course the web has coalesced around a set of standard layouts and visual language, as any media paradigm inevitably does, mostly because it has done so around a few standard frameworks. But then let's be honest, most Geocities sites kind of looked the same, too.