Then those researchers need to stop complaining when they get screwed over by Big Corp. I'm definitely not saying that the researchers shouldn't be rewarded appropriately, but we've seen countless times that, even with official bounty programs, these companies don't care about the researcher at all.

If someone still wants to put in all the work, that's great, submit the vuln and reap the good karma but they shouldn't expect more, even if the org they're reporting it to promises otherwise.