Inertia. It's the new 'nobody gets fired for buying..'
A previous project I worked on had relatively little traffic, and AWS costs were rather insane for that.
I proposed exploring OVH or DO and probably get costs down to 2 digits per month. Upper management would hear nothing of it - AWS was what they wanted, costs be damned. They were more protecting their own jobs than making a technical decision, I think.
AWS costs are insane for every project.
> Upper management would hear nothing of it
No one knows how to plan ahead any more. It's all "agile" and hardware (and budgeting for it) isnt something most in management are capable of doing any more.
There is also then justifying the CapEx on a 5 year amortization schedule... the thing is even if you borrow that money at current rate (7 percent) you can still come out far ahead of AWS... It's a lot of math, and a lot of accounting (and the accountability that comes with it).
Your average CTO just doesn't have these skills.
Unless the savings would be more than 100k Eur / 300k++ USD (I.e. total cost of one employee, it's not really worth it. Even then, moving to new infrastructure carries high risk for business disruptions which can cause an even bigger dip in revenue.
The cloud providers have definitely optimized their pricing for maximum profit extraction. Costs are high, and in many cases it's not high enough to actually warrant changing infrstructure to cheaper alternatives.
Sticking with AWS / Azure / GCP carries other benefits, too. You're more likely to find engineers who are experienced with those cloud platforms over, say, OVH.