> How did we get here?

I think the response lies in the surrounding ecosystem.

If you have a company it's easier to scale your team if you use AWS (or any other established ecosystem). It's way easier to hire 10 engineers that are competent with AWS tools than it is to hire 10 engineers that are competent with the IBM tools.

And from the individuals perspective it also make sense to bet on larger platforms. If you want to increase your odds of getting a new job, learning the AWS tools gives you a better ROI than learning the IBM tools.