The problem is that Mint already has a head start, is well-designed, and actively developed. Intuit had nothing like Mint, which made it easier for them to compete. Any Mint competitor will have to outdo them and/or fill a different niche.
Mint is likely going to rot, though, once most of the original people leave. That should give more than enough room to catch up. The hardest thing to fight will probably be the name recognition.
The former stands for a desktop version; the latter is probably known only by a small minority of the total mass-market (it's still a barrier though, I agree)
edit:spelling