The problem with Google, Meta, Amazon, et. al. is that they have a steady stream of income from their main business, and use it to enter new markets with loss leader schemes obviously designed to destroy their pre-existing competition...

I'm not from the US, but it seems to me like the companies you mention stay in their respective market and don't try to destroy competition in other markets, like Walmart is a supermarket chain, UnitedHealth is just health insurance, Exxon just deals with gas, JPMorgan Chase is just a bank, etc...,

meanwhile Google operated YouTube, Chrome, Gmail and other services at significant losses for years up until the point where they basically have monopoly in those areas because the competition couldn't keep up with Google's free products, and now when the competition is destroyed, they are destroying these free services with increased pricing or ads, neither of which were there while they still had competition in those spheres...