If there is a collapse, it will be brief.
There was a great video game collapse around 1983, due to games like E.T. which were terribly coded and not worth the plastic of the cartridge that housed them. As a result, the US lost its edge in the home console video game market, and didn't come up with a real competitor to Japan again until the Xbox.
As long as the manga industry in Japan continues to produce high quality series, then the anime industry will continue to animate them. Same with light novels. What seems to be becoming rarer is original anime and movies that aren't based on other things.