Miners/Stakers who is incentivize to validate the network and maintain the collective consensus.
All your points are valid and universally known but the more important here is whether or not those vulnerabilities are inherently caused by the nature of blockchain or tehcnical problems that we can/need to solve.
A good blockchain is not owned by anyone, any changes made need to go through multiple layers of peer review.
We are still very rooted in our current ways of doing things hence we are seeing phenomenon where companies are trying to take control by either building their own blockchain or centralised service on top of a blockchain. But if I travel back to the 70's and told you that someday you can run an Internet company, would you believe it?
We are no where near endgame but if you dig deep enough, you will see many exciting technical breakthroughs. One of the fascinating one is zero-knowledge validation. Blockchain could be the solution or maybe not, I don't care, I'm excited about the innovative opportunities that it brought upon.
If I understood what you were talking about, I would probably idly wonder how I could fit it in between being President of the United States, a firefighter, an astronaut, and a professional soccer player, but I wouldn't actually disbelieve it.
(Hey, in the part of the 1970s where I was alive at all, I was pretty young.)
Who is hosting the blockchain? Who is the trusted authority over the maintenance of the protocol that implements the blockchain, that all miners must use if they want to participate in the system? Who is it you're trusting not to organize a malicious 51% attack against the system, when it has already happened several times to quite a few blockchains? It is a blatant falsehood that blockchains don't have any trusted authorities. They actually require trusted authorities to function. You're not trusting "emotionless code" as the code is well known to have these flaws even by the admission of its own designers; what you're actually trusting is some game theory laid out by programmers you trust, that says the miners won't do bad things because they're getting paid. But in several cases we've seen that they actually will do bad things! And that's not even considering all the other bad things like fraud and ransomware that happens on blockchains that the operators seemingly just throw their hands up and don't do anything about. They don't even consider that to be their problem.
I hate, hate, hate that this line is used so often in discussion of cryptocurrency. It makes no sense at all. In order to have any kind of real discussion around this, the crypto community needs to move past these thought-terminating cliches.