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.