It's not simply creating a great product. If other things are really eating into their profits, the onus is on them to do something about it. Adapt or die. I remain skeptical of this supposed crisis, however.
Like I said, used sales have been around a long time, so how come it's only suddenly a huge problem for the industry as of a couple years ago? Piracy has always been a problem, though I'm not sure how much of a "problem" it really is. It's pretty hard to pirate PS3 games, isn't it? Yet that doesn't seem to result in proportionally better game sales compared to other platforms. By contrast, PSX games were super easy to pirate. And renting? That's gone down, if anything.
Everyone's an amateur industry analyst these days. I refuse to join the chorus of crocodile tears over those poor, defenseless game corporations losing profits to big mean Gamestop. I'm not Gamestop's biggest fan, but Gamestop didn't put THQ out of business.
If they get rid of used games, they've lost my business. Period. If you (general you, not you, personally) genuinely don't mind, that's cool. But apologism over it, and scapegoating Gamestop in the process, is ludicrous. When the game industry considers going in that direction, they will have to consider the balance between any recovered profits and the loss in profits from losing the business of people like me. If the former outweighs the latter, I will certainly not like it, but so be it.