Ok, but surely the problem there is that companies are (legally?illegally?) taking part in deliberately overreaching and anti- competitive work contracts.

And I mean hey, it's working isn't it? Can't show external evidence of your work and skills, now you're a bit more trapped here.

And I am sympathetic: those are completely unreasonable and anti-competitive employment terms, and I've had a past supervisor subtly imply they 'might own the intellectual property of all my thoughts', to which I can only offer the potentially useless advice of don't work there, or do work there but ignore/fight them.