Perhaps there's a reason why. The market generally doesn't need people who can do it all. In the same way it doesn't need people writing C++ or Rust to know how to write machine code or assembly. Sure, the ones that can are probably more knowledgable, but their experience with the high level language is more important.

I've done full-stack with no frameworks or non-std libraries (aside from PDO and OpenSSL, the limitations set by CEO decree) for about 8 years now.

I write my own schemas in IBM Db2. Hell, I wrote small application databases in IBM DDS in the AS400's SEU while I was still under the legal drinking age. I've always written our stylesheets from scratch, using SCSS. I've written C++ APIs that run in PASE, talk to the database with ODBC, then send back to a front end through sockets. I do graphic design and photography -- something I started back in middle school and took some formal classes on -- and have led the creation of marketing materials for multiple subsidiaries. I've spent 40 hour weeks working on sysadmin tasks in vim, 40 hour weeks writing libraries in JetBrains and VSCode, and 40 hour weeks working running around with my DSLR or working in Photoshop, Illustrator, and InDesign.

But when I look for full-stack jobs, most of them actually want somebody who is well versed in a framework. There's not much point in doing all of this from scratch. It's more tedious, more error prone, and it takes longer to get to market. Some interviewers have given the impression that I'm a little "less than" because I haven't used any major frameworks.

I think that's actually a valid take, and it's something I've started doing side projects to address. Frameworks improve velocity. Frameworks improve reliability. They reduce the risk of a developer coming up with an out-in-the-weeds solution to a problem they didn't properly understand. They make it easier to maintain the code. They make it easier to onboard new developers who are familiar with that tech.