When Vince dies the WWE will start to decline fast. There is going to be a lot of fighting behind the scenes. HHH is a wrestling guy but I doubt he has the business savvy like Vince to handle the shareholders, corporate business, etc.
Cena will probably be broken down due to not taking time off and the WWE milking him dry. WWE will probably have found their new mascot to replace Cena and he will probably be bland.
TNA will probably be dead unless they find the next star before the WWE does.
The indies will still be around but probably not making a lot of money.
I think a person or a major group will try to set up another company to really give us an alternative. I don't have a lot of faith in Jarrett and I don't think he has a lot of backing.