Well, the thing is: they
maybe can - Ripple definitely can, as it is existing and live for ~1.5 years now.
the ripple concept is a good idea, but Ripple the company sucks. Google Wallet, Facebook Wallet, and iWallet will all be building their own versions of Ripple.
It is under an ISC license, they even just need to fork everything. Paying someone to do that for one afternoon however probably already costs more than the XRP they'd need in their whole lifetime to use the existing Ripple network. I don't really see the appeal of forking off (which is stronger for pure "digital asset" systems like Bitcoin, which has been forked hundreds of times by now) but we'll see what the future brings.
