All competitors have just been weakened and many are seeking to preserve market share and/or autonomy (from regulation). furthermore, consumers largely hate banks at the moment. I certainly hate mine. If you have a big New Idea and the cash to implement it, it's a great time to offer an alternative.
Having said that, my experience with Paypal has been very good overall. And I have a jaundiced attitude towards Apple.
I don't know his reasons, but I note that the financial arm of most organizations with both a financial arm and another arm makes a huge fraction of the total income.
Examples include GE Financial and GMAC, GM's finance arm (which was sold off a couple of years ago to keep the auto arm alive).
Every industry has its barrier to entry, it is likely that the one for banking is probably at an historical low. Also Branson of Virgin said in an interview that he is applying for a license(or looking into it), so at least one of them actually does is for sure.