If you have an application where the performance and growth patterns are well known, cloud isn't a choice made for lowest cost. It may be best value for different reasons.

I've done ROI studies for several applications like that, and usually cloud has a higher total cost unless there are specific availability requirements or you don't have a facility that can meet a 99.9 SLA.

The key assumption is that you know a lot about the app and it's in a operating mode. If you're in a hyper growth mode, have fluctuating or seasonal demand, or you have no capital funds, cloud is a no brainer.