The point is you're writing mostly business logic and glue. You get a server request, you transform it with some logic, call some other servers, combine the responses and run some more logic, and return a response.
The scalability and interesting work has been factored out and handed off to infrastructure teams that build stuff like this auth framework, load balancers, highly scalable databases, data center cluster management tools, etc.
Which really is the smart way to do it. To the extent that you can stand on the shoulders of giants who've basically made scalability the default, you are free to focus on what you're actually trying to build. The only downside is if all the interesting engineering challenges are already solved for you, the remainder might not that be that interesting to people who enjoy engineering challenges.
