..and then mark it up. AWS overall has 38% operating margin[0]. Depending on your application this can hit you really hard (cloud egress bandwidth being an especially obscene offender).
> I'm skeptical that running your own data center will end up a cost saver in the long run.
It's not cloud -or- your own Azure-scale datacenter. There are any number of approaches in between including hybrid to offload stuff like CDN, storage, edge services, etc to cloud but the fact remains many companies can run the entire business from a few beefy machines in co-location facilities. Most companies, solutions, etc are not actually Google, Snapchat, Geico, etc scale and never will be.
Throw in some minor accounting tricks like leasing (with or without Section 179) and these kinds of "creative" approaches are often impossible to beat from a pricing/performance and even uptime standpoint. That's certainly been my experience.
[0] - https://www.theinformation.com/articles/why-aws-fat-margins-...