Cloud boxes are insanely expensive (easily 10x the price of the equivalent in house box, taking hosting, power, cooling, hw into account).

To make this work, you need a combination of variable demand, and only paying for partial salaries (your cloud boxes are mutualized with other people's boxes).

If you're a reasonably big company (tens of thousands of servers) , with fairly stable demand, and adequate capacity planning, you won't necessarily save a huge amount of money by outsourcing your DCs. You can argue that the gcp/aws guys are better than you at running fleets of servers and data centers , but at 10x the price, it's worth double checking. If all I do is raw compute 100% of the time on a very large scale, it's extremely likely I want to do it myself.

Obviously, there's more than raw hardware to the cloud, starting with all kinds of managed services, which can be worth it. Again , you'll have to do the maths :10x for the boxes, then extra for the distributed db? Does it give me a competitive advantage? Better time to market?

In the end, there are good use cases, and bad use cases for the cloud, and I don't think it's as clear cut as what you say.

EDIT : if cloud hardware prices were not completely ridiculous (say 2x), then it might suddenly be a lot more compelling, and I would most likely agree with you (security / regulatory issues aside).