'Ally' is not a successful startup. Ally is the rebranded GMAC, whose founding dates back to 1919. GMAC was renamed (and officially transformed into a registered bank) as part of a series of changes which included receiving over $16 billion in federal bailout assistance.
Eh, Ally isn't just "Ally Inc," it's "Ally Financial," and it uses the term "Ally Bank" in advertising its banking services. And Mint doesn't do banking at all — they're purely an analytics service.