I somewhat disagree. I'm in the process of building my 5th production rails app, and 8th web app (which will be used in production and make a profit). I've gotten ridiculously better at figuring out how to structure the underlying models.

This alone has made me way better at structuring databases for queries, planning properly, etc. My day job is more of a data science role and it's helped a ton to know how to build the whole stack.