Isn't learning maintenance, support, refactoring, testing, etc., also valuable (especially for beginners)? I think it's in the first page of Site Reliability Engineering that the majority of time and costs are present here, which might suggest it is a more valuable job skill.

As a beginner I saw posts like this and felt like this was the way to go to learn as quickly and efficiently as possible. In retrospect I wish I had stuck with a single project, such as a comprehensive Django application, gotten a job in that domain to extend my skills, and then built from there.