As any big player goes there will be 10 fighting to take there place.
If Ibill went I am sure Mike IA would have his boys write a better script and take their place!
If GFY, Porno Junkies, Net Pond and YNOT Masters went within 30 minutes the board scripts selling companies would have had a huge rush and the domain names :
www.netjunkies.com www.ynotpond.com would have been brought and their new owners creating fake aliases to make the board appear busy.
If a unkwon paysite with marginal webmasters went the traffic would just be redirected towards a big site.
I personnally reckon there wont be alot of companies going down totally but more over scaled down and even become a secondary income to the webmasters running them as they get 'proper' jobs.