For ML workloads anything between 6-8x cost increase for using cloud.

For CDN costs somewhere like 3x (they're pretty smart on discounts here, without those it could be 100's of x)

For compute somewhere like 3-4x (would be 6x before the discounts)

Managed DB is a hard one because the cost is really high but I'm not 100% sure how much time is saved with the solution they chose because while I saw the bill I don't work there.

It gets dicey with humans because it's apples to oranges, expensive SRE's who understand the inner-workings of cloud vs cheap(er) hardware folks who set things up from first principles with a higher up-front cost. -- FinOps with more traditional solutions is easier but you still need people for that.

Spotify's backend load is not entirely elastic. There are some elastic bits but a large chunk is pretty static.