The premise of personal computing is that my computer works as my agent. For any remote party that I'm interacting with - their sphere of influence ends at the demarcation point of the protocol that we interact with. Attempts to dictate what software my computer can run when interacting with them are unjust, and ultimately computationally disenfranchising. Despite the naive references littered throughout this thread to users being able to verify what software companies are running, it will never work out that way because what remote attestation does is magnify existing power relationships. This is why so many people are trying to fall back to usual the crutch of "Exit" as if going somewhere else could possibly tame the power imbalances.
Practically what will happen is that, for example, online banks (and then web stores, and so on) will demand that you only can use locked down Apple/Windows to do your online banking. This will progress somewhat evenly with all businesses in a sector, because the amount of people not already using proprietary operating systems for their desktop is vanishingly small. Which will destroy your ability to use your regular desktop/laptop with your regular uniformly-administered OS, your nice window manager, your browser tweaks to deal with the annoying bits of their site, your automation scripts to make your life easier etc. Instead you'll be stuck manually driving the proprietary Web TV experience, while they continue to use computers to create endless complexity to decommodify their offerings - computational disenfranchisement.
I'll admit that you might find this argument kind of hollow with respect to games, where you do have a desire to computationally disenfranchise all the other players so it's really a person-on-person game. But applying these niche standards of gaming as a justification for a technology that will warp the entire industry is a terrible idea.
Only if by "entire point of capitalism", you mean the philosophical paradigm that highly centralizing corporations market to gain more power and ultimately undermine the distributed sine qua non of capitalism.
> Saying otherwise is effectively suggesting that companies be forced to make product in a certain way to accommodate your requests.
You're missing market inefficiency and the development of Schelling points based on the incentive for uniformity. In this case specifically, the inability of a company to investigate what I am running on my computer creates the concept of protocols, and keeps each party on a more even footing. Remote attestation changes that dynamic, undermining the Schelling point of protocols and replacing them with take-it-or-leave-it authoritarianism extending further into our lives.