There are at least 3 companies with staff in developed countries well above minimum wage doing tagging and creation of training data, and at least one of them that I have an NDA with pays at least some of their staff tech contractor rates for data in some niches and even then some of data gets processed by 5+ people before it's returned to the client. Since I have ended up talking to 3, and I'm hardly well connected in that space, I can only presume there are many more.

Companies are willing to pay a lot for clean training data, and my bet is there will be a growing pile of training sets for sale on a non-exclusive basis as well.

A lot of this data - what I've seen anyway, is far cleaner than anything you'll find on the open web, with significant data on human preferences, validation, cited sources, and in the case of e.g. coding with verification that the code runs and works correctly.