I do believe that the market can and should decide most things, but not everything.

Screen size of the average mobile phone?
The consumers have spoken. Apparently we all have giant hands and prefer to carry around a full sized monitor in out pockets rather than being able to operate a device conveniently with a single hand. I utterly hate this trend, but oh well, the consumers decided, the manufacturers listened.

Headphone jack on a mobile phone?
The consumers have spoken. We are happy to believe the manufacturers' lies about the headphone jack, how it's a frequently failing component and how we're better off buying their bluetooth earbuds instead. And since everybody should only ever use bluetooth why do we even need a headphone jack? Again, I'm super frustrated by the absence of the headphone jack on modern phones, but... the consumers decided and the manufacturers listened.

"Repairability" of a mobile phone?
This is a much more complex attribute than the above and not easily assessed by the average consumer at the time of the purchase (or is there such a thing as a repairability score label?). A "bad" decision will only surface months or years later. And if the mobile phone industry as a whole is moving into the direction of making phones gradually less repairable, then what choice does a consumer have other than not buying a phone at all?

The average Joe is a rather selfish consumer. What does he care about the total amount of electronic waste we're producing collectively? Some choices are better not left to the consumer, otherwise we'll be using single-use plastic bags for another century. If something is counter to the interest of the suppliers and the consumer's decision impacts more than just the individual, then regulation can be a solution.

Regulatory actions can have various forms. It doesn't have to be a strict prohibition of something, it can also be a tax that nudges the market participants into the "right" direction. Yes, of course it's debatable what is actually "right". Yes, regulation can go wrong, politicians are corrupt etc. But I find the stance of being categorically against regulation of any form and scale quite radical.

Disclaimer: I didn't read TFA.

My understanding is that the right to repair movement is not about placing repairability as the highest priority (above compactness etc.) and mandating this as such, but rather about not allowing manufacturers to introduce arbitrary hurdles to repair "their" devices. I put "their" in quotes because that seems to be the sentiment that we're transitioning into: it's not you, the consumer, that owns the device and can do whatever the f%@k you like with it... No, for some reason the manufacturers would like to have a say in what you are or are not allowed to do after you purchased said device.

You guessed wrong, I tried Xfce on Debian.

Are there any resources that actually back Xfce's claim of being "light" in comparison to GNOME?

I tried Xfce several years ago and while it was nice and easy and all, I had the feeling that with a bit more memory I could just as well run GNOME with obvious benefits (feature-wise).

Today the situation is still the same IMHO. Sure, Xfce has probably a lot more features nowadays, but so does GNOME. I see the benefit in the GNOME framework: it's mature and stable, and more or less customizable. I guess it would be possible to strip out some GNOME services (e.g. desktop search) if memory is of concern. CPU usage shouldn't be an issue with GNOME (unless some background service runs, which again could be turned off if not wanted).

With that in mind: how does Xfce compare to [a minimalistic] GNOME regarding resource usage?

Note that I'm not a GNOME fanboy (I use a plain window manager), but right now it's the desktop environment I'd recommend to others.