I've had a similar take on things, but with a slightly different set of counter-beliefs:
> Problem: If the reality of the situation is that you aren't actually lacking in skill, this works. However, if your peers legitimately outclass you, you're just tricking yourself -- which presumably won't work for long.
Maybe I am as good as my peers, maybe I'm not. Who cares? There's room for junior devs, senior devs, and technical leads in the same company. The more important question is: Am I helping create value? That's our shared goal, after all - our skills are merely the means to achieve that. Assuming the worst case scenario for a moment, where I'm literally on the bottom of the totem pole:
If I am fixing simple bugs, those are bugs my betters don't have to fix.
If I am implementing simple features and tools for our users or managers, those are simple features and tools my betters don't have to fix.
If I'm writing simple dev utilities and debug tools for my coworkers to use - even the simplest things like missing container visualizers, for example - I'm enabling my betters to be even more productive than they already were.
If I'm soliciting feedback for how to improve, and pursing self improvement, I shall continue to close the gap, however slowly. And even now, the best of us have blind spots and weaknesses that even the worst of us can help cover for. And being surrounded by my betters means I will improve quicker, as well.
My betters thought that whatever I'm working on important enough to pay someone to implement - and even if they're wrong about that, there's value in finding out they were wrong.
...there is a potential problem with this, but "there's no value in even trying this, why is management committing to this waste of resources - this waste of my time?" isn't a problem of impostor syndrome, at least ;)
> Problem: This works when your peers aren't actively negatively judging you. But, how are we to determine if that's the case? Lack of evidence isn't proof at all -- especially in a work environment, social norms are that they won't express negative criticism to you (even if you ask for feedback).
Lack of evidence isn't proof, but there's statistical considerations as well. Surely someone won't be perfectly tuned into the social norms, and be straightforward and honest. This lack of evidence that you're an impostor is actually evidence that you're not one!
We can improve this further by extending the benefit of the doubt to these peers we're looking up to (which tends to be easier than directly giving ourselves the benefit of the doubt.)
Most of them probably aren't harshly judgmental misanthropes. Everyone started somewhere - no matter how great they may be at it now, at one point they weren't that great. They would not judge their own pasts so harshly. And should I be proven wrong about a few exceptions? Well, that says more about them than me! The exceptions should earn my scorn or pity, not my investment of self worth. If it's more than a few exceptions... well, that says more about the job than me.
I do still care about what my peers think of me, but only the ones who aren't assholes. The assholes can go fuck themselves. This feels harsh, but hey - turnabout is only fair play, right?
Now - are there areas we can improve upon? Sure. All of us can stand to improve further. And our coworkers and managers may get frustrated if we can't accomplish all our goals within our given timeframes, without being assholes - but they tend to be the sort who would simply set more and more ambitious goals until we couldn't no matter what our skill, no matter how large our team. I'd know - I'm one of them ;). If you can, don't take our infinite appetite for progress personally. Don't sacrifice your productivity and your leisure trying to crunch to achieve them either - you'll only further encourage the beast.