I have long worried about the network too, tbh - as more and more people can't set up the kind of rig you'd need to mine in their basement because of how costly it is to do so now, it's moving to mining farms. Theoretically people own shares in these and that's all well and good but what's to stop a big company (like Blackrock) from owning a mining farm and suddenly not renewing everyone's contracts or buying them out or however that works to own shares when they've amassed the 51%, or gone in cahoots with other companies where combined they own 51%? The harder it is to mine, the less decentralized it gets.
I appreciate Bitcoin for starting the ball rolling, but I really don't think it's the best at all. All the things people complain about crypto for, especially the electricity use, are things that Bitcoin does and I'm constantly having to explain to people that not all crypto works the same.