Bitcoin will have to change DPoS (or something very similar) when the community realizes that the merchant providers hold more power than the miners.
I think it will happen much sooner than most people think.
What do you think would happen if Bitpay, Coinbase, Circle, etc., threaten to take a hard fork Bitcoin?
I don't think it can happen that fast. I would guess if the the Bitcoin foundation is wiling to change to DPOS then it takes another 3 month to change. The public discussion whether to change or not might take 2 month. So half a year from when the Bitcoin foundation basically thinks it makes sense to switch.
Any more educated guesses?
What is the plan for Bitshares? Financing and running an own payment provider? Making Bitpay accept Bitshares / BitUSD before Bitcoin can switch?
What would be advantages of Bitshares + DPOS vs. Bitcoin + DPOS?
I would consider 6 months fast, but 3.5 is much too long - that would kill Bitcoin, IMO.
I think for quite a while, Bitcoin will still be "Bitcoin!!!!" - the worlds next currency!
Bitshares will be everything else.
My view has been:
Bitcoin: Currency, Highest-profile Ledger
Bitshares: Business, Wall Street, Internet, etc.
Ethereum: Internet of things
Regarding Bitshares adoption at the merchant providers - wait until they try out DPoS for themselves - it answers the coffee shop conformation problem.