Discounts on console are not something TFP can do on their own. The consoles themselves (Microsoft and Sony) have to agree to this. In this instance, TFP was able to get a discount for people who purchased a digital copy of the console game but were unable to get approval for discounts for people who bought a physical copy of the game. That's not TFP's fault. That's entirely Microsoft and Sony. As far as getting the new version, this is really not any different from buying newer versions of something like Madden. The old console game and this new version are so different from each other that they are actually more different than Madden 23 and Madden 24. So even if it wasn't a problem with the old console developer going bankrupt, it still might not have been free.
I understand the issue, especially when PC players don't have to buy it again, but consoles are an entirely different beast. TFP can basically do whatever they want for PC. Yes, Steam has rules and requirements, but TFP could just sell it somewhere other than Steam if they wanted to. But with consoles, they have no option but to go with whatever Microsoft and Sony say.