Note that this is just my gut opinion on it, imagining the nightmares I've seen in healthcare integration and contrasting that with what I see as an end user of Bank integration. I've not actually seen the business deals and effort in the backend as a developer in the latter case, but as an end user of Mint I've seen missing integrations that hint strongly at the difficulties they must experience.

I think the reason why is because it's a pretty large integration undertaking. To compete with Mint at this point, you'd have to offer similar levels of integration with banks, credit card companies, investment companies etc...

The problem is that there are literally tens of thousands of these companies, each exposing their own APIs and each with their own unique caveats as to data they require, throttling limits, back-room deals for access, hesitation to even let people access their systems etc.

For an anecdotal end-user example, I have an account with one provider who refuses to cooperate with Mint in integrating - ECSI. This is a small lending company for student loans, one of thousands of such companies. They decided for reasons that are not publicly available to not even allow Mint to integrate with them anymore, after having let them do so for the first couple of years. What sorts of negotiations were occurring in the back end between these companies, and what caused it to fall apart? The public doesn't know, but needless to say there was some level of custom integration effort for them, some level of business negotiation, and then finally something fell apart and made customers mad as a result. Now, all of this integration work and business negotiation had to happen between Mint and ECSI - and that is just one of the tens of thousands of companies out there. It is a very tall order to ask a new company to come forward and make that much upfront work in order to get on par with Mint so that it can start competing.

The real fight that would make more innovation in the field would probably have to start with getting companies to standardize and expose their APIs without (or with common and well understood) strings attached. If this happened - as has been struggling but slowly improving in the Healthcare field - it'll become more feasible for a company to realistically compete with Mint. And then you can get to those enhanced features that Mint suffers for want of. (however, at that point Mint's significant engineering force could be redirected from integration efforts to these same features, and then you'll find yourself fighting against a much larger machine now bent on feature improvement)