Need help understanding decentralization

Hi, All, Please help me understand something about decentralization vs centralization and the impact of unequal wealth distribution. If for example, Apple were to buy the majority of ETH, would that turn the ethereum network from a decentralized platform into a centralized platform given the majority is now owned by a one big, mega entity?

If ethereum still remains decentralized, what mechanisms does it have to prevent a majority holder like Apple from owning the entire system? Does this apply to all other cryptos like solana, Bitcoin, etc? Is

My deepest apologies if this is a dumb question but please help me understand. Many thanks for your input and help.