Bezos ran at a loss for so long it drove out actual and potential competitors.
Most (or all?) of the recent titans seem like each has his own company town. (See https://en.wikipedia.org/wiki/Company_town )
While their activities certainly fall in the realm of capitalism, and are just blips at longer time scales, it certainly feels like capitalism has been a bit under the weather for the past couple decades.
Regarding the money invested in AI, it all gives me "irrational exuberance" vibes.