I wouldn't be surprised that in the near future Primedice will be closed or will be merged on Stake site, just my two cents.
Why would they even shut Primedice down? There is no point to do that. There is a dice game on Stake as well. Some people like Stake while some prefer to keep playing on Primedice, its just a small matter of preferences.
Primedice has been operating from 2013 and everyone knows primedice, it will be there and it will always generate decent amount of traffic. Even if you google best bitcoin dice site right now, Primedice will always pop out as the top list. The name itself is already an exclusive brand in gambling scene