At the same time, don't you think the situation with 21 is different from Google (and I'm not even convinced that Google is under the thumb of the government and a 100% compliant slave, or acting only in self-interest without regard for consequences)?
No. 21 is a "Bitcoin" company, Google is an Internet company, Exxon is an oil company, Apple is a computer company. That doesn't mean their core values align with what is best for the resources they require. It doesn't mean what 21 wants is best for Bitcoin, what Google wants is best for the Internet, or what Exxon wants is best for oil distribution. The common theme here? These companies want to control the resources to exploit them maximally for short term profits. Their attempts to exert control are what we should be afraid of, because it's relatively clear that their interests will not align with the most utilitarian action in all cases.
Would 21 owning 60% of hashpower be good for Bitcoin? Maybe they will do an internal study in 5 years and find that the answer is yes, because the network will have faster confirmations, more hashpower for security against other non-21 adversaries, more consumer confidence with mining based in the US instead of China, etc. The point is they can spin whatever they are doing as good for you and good for Bitcoin, but what they will ultimately consider is what's good for themselves. This is just a natural consequence of the corporate structure... corporations are single-purpose entities, their purposes being to maximize their own profit, not to secure some abstract ideals like free networks. If at some future point they see more profit in decreasing the freedom of the network, they will, regardless of the blowback from some diehards.
The point is that the Bitcoin network represents a commons that anyone can access, and 21 is simply one participant in that network (which I believe we can trust that they realize, and that they do their best to be a good actor within that network).
Yes, but this will not stop them from attempting to influence the network in ways that benefit them. You are their audience right now, so of course you're getting what they want you to hear (exit, new system, cypherpunk, fuck the establishment, etc.) But if 21 becomes the establishment and their average customer is then your mom or the guy on the street who thinks Bitcoin is a "drug currency", they will do what they think is best for themselves and their users, which may not be what's good for the founding ideals of the network as a whole. For example, what if they get a bad image as creating untraceable money for drug dealers, and they start doing blockchain audits on the funds that are mined by their chips. What if they then see a reasonable step as complying with the FBI's demands to share that data? They are acting against the values of the network to subvert it, but still acting in their own self interest and (what they claim is) that of their users.
Google does not gain anything by hijacking the internet protocol (TCP-IP or whatever); they just use that network for their business and in fact do what they can to protect the integrity of that network (trying to expand internet access with Google Fiber, Project Loon, Android, etc.).
That depends on your definition of hijacking. I'd argue putting ad cookies all over the Internet to track and build profiles on users who think they are surfing with some level of anonymity, blocking Tor across all their services, requiring mobile numbers for "Google" accounts that are increasingly pervasive, data mining users with no clear disclosure, and offering services like Chrome which track users even across non-Google services (keyword complete, webstore, etc) are all subverting the core values of free networks and a free Internet. Google doesn't see it that way, to them they are helping the Internet and offering useful services.
The same shit is going to happen with 21. They are going to "help" Bitcoin by enforcing whatever they think is best for the network, towards their own self interest, regardless of the rhetoric of the founder. He can be as "cypherpunk" as he wants, but when Goldman Sachs comes and tells the investors that they need to cut that rhetoric if they want a $1B partnership I can tell you some tunes are going to change right quick. My point is that if you want to build a new system, you should not have that effort spearheaded by a company who is part of the old system. If that same company then pretends they are the new system, what they really are is the old system using clever marketing in disguise. Anyone who really believes they are different has fallen for that marketing.