As far as a practice of mindful examination: yes, this makes sense. Examining your thoughts, and the spoken assertions of others, is valuable if only to train critical thinking.

I do think it's possible to prize independence in this regard too much, though. Taken to the extreme, it's a sort of personal not-invented-here syndrome: it can shut you off from valuable sources of ideas and mentorship, and cause you to endlessly re-tread mental ground that's already been covered. Taking the successful scientist as an example: they "stand on the shoulders of giants", and their "independent" thoughts are only possible because they're immersed in, and actively synthesizing, lots and lots and lots of "conventional" thought.

The "independent" breakthrough is just one small iteration on heaps of "conventional" thought. The "independent" product is just one small iteration on heaps of "conventional" technology. It's the deep familiarity with the "conventional" part, and thinking through what all that really means and makes possible, that makes the "independent" part possible.

So: are you really thinking independently? Or are you just thinking blindly, without that familiarity?