This has always been true in every craft, and it remains true for programmers in a post LLL world.
Most training data is open source code written by novice to average programmers publishing their first attempts at things and thus LLMS are heavily biased to replicate the naive, slow, insecure code largely uninformed by experience.
Honestly to most programmers early in their career right now, I would suggest spending more time reviewing code, and bugfixes, than writing code. Review is the skillset the industry needs most now.
But you will need to be above average as a software reviewer to be employable. Go out into FOSSland and find a bunch of CVEs, or contribute perf/stability/compat fixes, proving you review and improve things better than existing automated tools.
Trust me, there are bugs -everywhere- if you know how to look for them and proving you can find them is the resume you need now.
The days of anyone that can rub two HTML tags together having a high paying job are over.