One thought I had recently: Their shareholders are probably mostly the same people. So why even compete?

I don't know, there doesn't seem to be much overlap to me. Apple is a hardware business, Microsoft is software, Google is search, Facebook is social media, Amazon is distribution and compute. They do have their fingers in each other's pies but not to a large extent.

Stakeholders expect (and price assets for) endless growth.

Which is a godsend for the users. Can you imagine a world where there is only one big cloud provide, say AWS, and all the big companies with the infra just sit out? Can you imagine how expensive AWS would be and how much power it has over the users?

Isn’t this something like how everything ends up evolving into a crab?

They’re just turning into conglomerates.

It was common in the post wwii era in America and its Asian allies like Korea with its chaebols and Japan with its somethings I can’t remember the name of. The Asian countries forms were normally based around a single family, we’ll need more time with the current US form to see if they are also dynastic

They'll just buy the competition once it seems like it's at a good price. Capitalism leads to concentration.

That’s what happens when you print trillions of dollars. Suddenly investors have too much Monopoly money and they want to spend it on something, anything, that might not make as much of a loss as holding cash during the subsequent inflation.