Then what does a patch do? What happens if, even with patches, people just start anticipating IGAU2? You yourself just said it wouldn't be revived because MKX is coming out, so how does a patch keep that from happening? It's because people don't want to play IGAU anymore and do want to play MKX. A patch wouldn't save or change that, it ultimately comes down to the people.
Of course, an update always shines a light on a game. Skullgirls got a renewed interest after Encore was released, DoA has renewed interest with Last Round. But that doesn't mean the games sustain interest or keep players. Again, K.I. gets frequent updates, characters, stages, and more and, at TFC or NEC or some recent tournament, it got less entrants than MK9. M.K.9.
They still do fix true BS like the Batgirl infinite, Sinestro pushblock, and Harley B3 being clashable. They just didn't do anything else with balance. Regardless, you are not forced to pay 30-40 to get the most recent version of the game, it is 100 percent optional. Super, AE, and Ultra you must pay for those versions or you don't get the update. Meaning, if you're a competitive player, it renders your current disk/download useless as you have an out of date version unless you shell out more money.