Like all markets they can be monopolized. You are assuming quite a bit by presuming that the market works perfectly according to rather basic economic principles.

There are all kinds of reasons someone could be more desperate. Perhaps they have a significant skills gap. Perhaps they don't have citizenship. Perhaps their health care options are artificially limited. You invoke supply and demand but you narrow your focus to a single interface when it's obvious that wouldn't be appropriate.

It's not about "penalizing corporations" it's about "being honest about their motives." Unlike many on HN I refuse to handwave away this thorny and uncomfortable process.