They do have an enormous amount of control over them, but the bigger issue is that standards are not that relevant given that all developers will test their stuff on Chrome and basically it (slower Firefox on Google sheets? Pause when opening YT documents? Who cares!).
It's not a cliche, it's sad reality. It doesn't have to be thought-terminating, though - some people try to do something about it.
Don't know what YT documents are, but FWIW my experience with Firefox on Linux is much better when using Google's products than Edge on Windows. Maps, in particular, is an unbelievable dumpster fire. It lags like crazy and has extremely weird behavior. Think the map's labels showing up in the search box for a second. When panning, it seems to reload pretty much everything byte by byte.
The only thing which works on Edge but doesn't on Firefox is casting from YouTube to my TV, but since this ignores my adblocker I never use it anyway.
The comparison is done on the same physical machine, with the default Edge config (I don't use windows that often, so don't bother to change settings).