Since you are talking about proprietary software, I assume you mean fixing bugs by the corpo devs themselves.

Well, this would imply broken software. You already payed for the software, now you are required to pay to get bugs fixed? Bad optics, although not beyond contemporary sentiments... Inherently shady incentives: https://en.wikipedia.org/wiki/Perverse_incentive

This kinda only works best for FOSS, incentivizing external devs IMO.