Does Google still provide a "significantly worse" experience if the user agent is Firefox? I recall that was true on Gmail and Youtube for a while.
You can sometimes trigger similar changes in appearance to the search results view by switching to incognito or clearing your cookies - Google often A/B tests or performs slow rollouts of changes like this, a difference in appearance could just be because a new user agent string got you placed into a different release group.
Incidentally, this is far from the first time google has been caught heavily optimizing exclusively for their own browsers, which, to be clear, is quite probably not explicit policy - but is monopolistic abuse nonetheless. Remember the youtube polymer redesign? The Edge HW acceleration-breaking invisible layers? I get the feeling they just don't test in other browsers nearly as well.
Given google's history here you really shouldn't be giving them the benefit of the doubt in this matter; at best they're consistently, repeatedly negligent; but it's at least conceivable there's culture of giving additional other google teams; which is a form of monopolistic power abuse.
Honestly at this point I’d like to give up on the user agent header and have everybody say they’re Chrome all the time.
Not a fan of Firefox and I refuse to like or use chrome.
Yawn.
IIRC though the main issue with YouTube was a slow polyfill library which has been fixed since they updated to the standardized version of Shadow DOM.
In which case Firefox blocks a lot of trackers so naturally their marketshare appears less than reality.
While this is not nothing, this should be a few 0.x % of global browser marketshare
I use user agent switcher sometimes to poke around on sites, YT is totally broken and I ditched using google search about a decade ago due to their policies.
https://addons.mozilla.org/en-US/firefox/addon/open-with/
(If your desktop environment supports drag and drop, you can also drag and drop vimeo or youtube URLs into mpv.)
[edit] picked the first video from "staff picks" on vimeo and it worked fine in FF:
I've always found the old design better (just like reddit), so I disabled polymer for YT and got both more performance and better UX out of that deal.
To try it out, just append &disable_polymer=1 after any YT video url.
Even after more than one year you can still not make a one-line space between paragraphs in YT comments without editing the comment afterwards because YT will always insert additional empty lines for whatever reason.
It did though. See this comment: https://news.ycombinator.com/item?id=21826191
They claim to be open and most things are opt in but im not sure why their "human web" is not opt in.
https://news.ycombinator.com/item?id=20058697
And the back and forth on whether you really need it:
I don't use Chrome, so I can't tell how bad it is on a comparative basis, but (especially in private browsing mode) Recaptcha can make you cycle through a half-dozen different images looking for the traffic lights or what not before letting you continue.
That's when I just leave. If I'm feeling nice, I'll drop the site owner a note explaining why, but usually not.
Nobody's site is that great.