As much as people wanna mock ratings and their recent attendances, stuff like that will never make them close their doors. They're still doing better than ever financially and have been going strong for the past couple of years now, despite the network only being 10 bucks a month instead of the 50-60 bucks they used to cash in for PPV.
WWE's booking/writing isn't necessarily connected to their financial standing, given that advertisers and TV stations still see them as the #1 world wide wrestling organisation (which they still are). Also, as a publicly traded company, it's more of a business than a wrestling promotion.. so as long as they make the right business decisions, they'll be around for much longer than most other promotions, that's for sure.
Therefor, the only reasonable scenario is Vince dying and Triple H not being able to keep it going as a business. We all know that Triple H has a feel for the wrestling and entertainment stuff, but he's still learning and adapting to being a business man. So hopefully Paul's not putting control in the wrong people's hands and still learns enough from Vince before he's able to take full control of the company. Which is still quite unlikely, given that there are so many other people involved in this thing