Forums like LinkedIn have had regular listings in recent times looking for programmers to help train new models for answering programming questions and generating code. However, the rates offered are nowhere near enough to compete with real programming jobs for skilled developers, at least not in the major Western economies.
One wonders what quality level these new models will actually be trained at. Given that these roles are kinda-sorta asking professional programmers to train themselves out of a job, one also wonders whether 100% of those who do contribute will be doing so in good faith. And as you point out yourself, there is also a risk that the “original” content is anything but.
Given the scale of the data involved here, and the sheer amount of skilled human input that would be required to refine that data set manually, it seems unlikely that a Mechanical Turk strategy alone will solve many fundamental problems here.