What about mining pools? Top 3 pools now have more than 50% of hashing power (meaning total control of the network), and corporate agreements between 3 entities are not exactly rare.

Bitcoin isn't a company, though.

Well, the development of Bitcoin Core is highly susceptible to corporate influence as seen by what Blockstream did in the past (which is less now and more diverse), but still, it can happen again in the future should there be any contentious issues in the community.

Why is it that Lightning Network seems to be the only L2 solution with Bitcoin? Because it’s a Blockstream product.