>> it's getting more difficult to flash ROMs onto most phones, not easier

Turns out, that is a niche use of a phone. Few people really need it.

But, some of them post on Facebook and Twitter "here is how to flash your phone and get unlimited games"

... and then many of those get bricked or attacked by viruses, and/or get otherwise disabled, and now the provider needs to deal with the tech support issues.

Plus, the ads may be redirected to someone else.

So yeah, if I was Samsung or Apple, I would not want you to flash the ROMs.