Updates changing defaults, refusing themes, killing extensions, etc

A thread in the mozilla.firefox NG asserts that 85.x, like 78.x, changes 
the Update default to Automatic. Actually, automatic update has been the 
default for FF and TB for some time now. But it grates when an update to 
change a default from the user's preference.

I eliminated TB 78.x and installed 68.12.0, the last one for which my 
fave extensions still work. Even so, it won't accept themes, which 
Mozilla in its infinite wisdom has decided should not be allowed any 
more. Well, Mozilla should at least offer infinitely variable colours 
for the standard theme.

But the main problem is the extensions. IMO, the functionality of most 
of them should be included as options in TB and FF. I know that most 
people will use the software as it comes, but when tens of thousands of 
people install extensions focussed on the same functionality (eg, 
control over fonts in TB's folder pane, etc), then surely that should 
tell the devs that there's real need for that functionality.

I see that FF has been losing to Chrome. I don't think that's entirely 
the result of Mozilla ignoring users' plaintive pleas for improvements. 
The power of FF has always been customisation. The latest versions 
reduce that power. So what's the difference between FF and Chrome or 
Edge? Not much any more. Hence not much incentive for switching to or 
keeping FF.