No, no. The costs cloud saves are in staffing and opportunity costs. Everyone knows that it is more expensive than a comparable server, but...it is easy, standard, and available. If you want to a) not have real estate capex, b) not worry about the core ops part of your applications, and c) used to outsource infrastructure to a managed service provider anyway, then Cloud is a viable value prop. Plus, the more of the services you use, the more you app stack becomes "standard" parts with glue code. This is maybe an improvement at the large enterprise scale where home-built apps don't have a reputation for being future proof.
And better credibility when you say “Our vulnerability was on AWS and configuration is hard, but at least we had the default VPC config” rather than “We maintained our own stack and being sysadmin is hard, and the port was exposed on the web.”
Modern cloud services such as S3 or let's say MongoDB seem to have a lot more security footguns than old-school bare-metal. An S3 bucket misconfiguration exposes your data to everyone even if there was never a reason for that data to ever be exposed to the outside world. On a bare-metal, chuck it in a directory outside your web root and someone will have to actually breach the server before they can steal the data.
The thing is, most webapps don't use a lot of services. Backend-Logic in whateverlanguage, a database, and a webserver. Maybe hooked up to some CRM system. That's it for 99/100 webservices.
Yes, the services cloud providers offer are amazing, they are complex, and it is natural for developers to be fascinated by complex things (I know it is for me). But it's important to realize when simple is simply enough.
