It seems that it's faster on every website I use except Gmail, Google Voice, and Youtube. I wonder whether Google is using some sort of Chrome-specific javascript to make those sites run faster in their own browser?
I'm not sure if this is still the case, but Youtube used to use WebComponents v0 which has to be emulated in JS in non-Webkit browsers, since only Google ever implemented v0, while everyone else agreed it required a bit more work, and other engines run v1 instead, which is not compatible.
The main YouTube site seems to still be lousy in Firefox. Buttons that should open dropdowns (e.g. the top right corner user icon and notifications icon) don’t. If I want to actually see notifications, I need to tack ?disable_polymer=1 onto the URL and experience the ancient site!
YouTube Studio doesn’t suffer from these problems.
I have no idea when it stopped working, because I scarcely ever used the affected buttons until very recently—I have a vague feeling it might have worked three or four years ago, but in the last couple of months it’s definitely not been working for me.
uBlock Origin is the only extension that I have that could feasibly alter anything, and all it’s doing is blocking googleads.g.doubleclick.net. Nothing of interest shows up in the dev tools. 99.9% sure the bug is with YouTube, though in what particular way I cannot guess.
Ah hah! Figured it out: some cosmetic filter is killing the dropdowns. Unfortunately the effecting rule is not discernable in the dev tools, so figuring out which rule is at fault is tricky and slow.
Found which one, too: it was a rule of my own that I added almost a year ago to kill off some of the annoying cards they pop up at the ends of many videos, which hide the video content; turns out my rule was just a touch too broad for how they do things.
It doesn't exactly need to be Chrome-specific; every browser/JS engine will have slightly different performance on different workloads, so Google just has to lean heavily on things that are golden-path for Chrome. They could even do this accidentally/nonmaliciously just by mostly testing on Chrome and not testing performance on other browsers.
Wouldn't it rather be "Maintaining and not fixing" rather than "Designing"?
Google is perfectly allowed to make mistakes or forget something. The criticism is that this is a repeated behavior, as if they decided that it is never going to be a priority.
Nothing specifically malicious. Since Chrome is default browser at Google, it’s used as default development and profiling browser, and then it’s ported to and tested on other browsers, obviously not as much.