I grew up during the dial up era of internet and remember how insane it was each time the technology improved, broadband, dsl, fiber etc.
I wouldn’t expect pages to instantly load, but I have to imagine all the data farming is causing sites to be extremely bogged down.
Well if you just try to load a news website with and without an ad blocker you will usually notice a huge difference. So yes.
But also, technology has become much more complex compare to the beginning of the internet. So every piece of software is more bloated than it used to be, sometimes for a good reason, sometimes less so.