What you fail to take into account, is that geeks like being able to freely goof around with stuff; and that new disruptive tech evolves precisely in the ecosystems where geeks are goofing around with stuff.
Consider the dichotomy between iPadOS and macOS. macOS still exists — and still has things like the ability to disable Gatekeeper, enable arbitrary kernel-extension installation, etc. — because the geeks inside Apple could never be productive developing an OS on a workstation that is itself a sealed appliance. They need freely-modifiable systems to hack on. And they may as well sell other people those free systems they've developed — with defaults that make the tool appliance-esque, sure, but also with clear paths to turning those safeties off.
The same thing was true in the 90s with the rise of walled-garden ISPs. The average consumer might be happy with just having access to e.g. AOL, but the people who work with computers (including the programmers at AOL!) won't be happy unless they can write a program that opens a raw IP socket and speaks to another copy of that program on their friend's computer halfway around the world. And so, despite not really mentioning as a feature, every walled-garden ISP did implicitly connect you to the "raw" Internet over PPP, rather than just speaking to the walled-garden backend BBS-style — because that's what the engineers at each ISP wanted to happen when they used their own ISP, and they weren't going to tolerate anything less.
And then, gradually, all the most interesting stuff for consumers on the Internet — all the "killer apps" — started being things you could only find the "raw" web, rather than in these walled gardens — precisely because the geeks that knew how to build this stuff, had enthusiasm for building it as part of the open web, and no enthusiasm for building it as part of a walled-garden experience. (I would bet money that many a walled-garden developer had ideas for Internet services that they wrote down at work, but then implemented at home — maybe under a pseudonym, to get out from under noncompetes.)
Even if there comes about an "attested Internet", and big companies shift over to using it, all the cool new stuff will always be occurring off to the side, on the "non-attested Internet." You can't eliminate the "non-attested Internet" for the same reason that you can't develop an Operating System purely using kiosk computing appliances.
The next big killer app, after the "attested Internet" becomes a thing, will be built on the "non-attested Internet." And then what'll happen? Everyone will demand an Internet plan that includes access to the "non-attested Internet", if that had been something eliminated in the interrim. (Which it wouldn't have been, since all the engineers at the ISPs would never have stood for having their own Internet connections broken like that.)
The companies have an imperative, since I guess calling it a vested interest would be an understatement, to not let you escape from their clutches.
They can't force you to come inside, and they can't force you to stay, but they can make it so that it's almost impossible to go anywhere where they are not already there. It's creepy and predatory vulpine super stalker behavior, but unless we establish a system of government that puts our desires above theirs there is not much we can do about it other than stay away to the best of our abilities.