Agree, but as much as possible should be limited by reading other code. If one spends 95% living in his own bubble, he will likely progress slower.
> Sure, there may be "excellent code" out there by some standard, but nobody can agree on what "good code" is.
The exact semantics of "excellent code" don't matter here. For all practical purposes, "excellent code" is what a "hey I am a python beginner please tell me your three favourite codebase to learn from thank you" thread on reddit yields.
On the other hand, it is stupid to ignore advice by experts. It is also stupid to not become able to recognize experts. This is a very important step in becoming good in any field - recognizing people who are better than oneself.