The development of simple sites has become a commodity many years ago. In the presence of a large number of CMS and frameworks, the barrier for building a website has significantly lowered. And what if you need to develop a Web service that will be used every day by several hundred thousand, and even millions of people?
You would have to solve the performance and scalability problems, caching and load balancing among the servers, which requires much more effort than the banal development of the web server UI.
We have successfully implemented several high-load web services that demonstrated high reliability for several years of operation under high load.