If they did, will it not threaten bitcoins and altcoins because the common people who haven't heard of bitcoin before might choose to use these bank/government-created coins instead? Do we really need more coins?
I am not entirely sure if governments will have their own (wish they do) but I am 100% sure that banks will have their own coin.
Even if not for anything related to customers they may end up doing it as a test, sure that won't be official and be used but they know they need to check out blockchain and how it works so they will make a new blockchain currency for themselves and they will definitely want to implement the best parts of blockchains into a currency, that would have been something awesome but we still don't know if they are doing it or not. Sure they must be working hard on figuring it out but not sure if they have implemented any parts of it.
Some banks are working with Ripple for some huge movements we know that but that's about it. Banks need to adapt because if some banks implement it they will make it cheaper and faster so they will get ahead of the competition and all others HAVE TO work on it to catch up so it is going to get common eventually.