Just because the show's cancelled doesn't mean the franchise is going to die. I mean, look at Scooby Doo. That dog's been around a good 40 years and STILL making new movies/series.
Give the Turtles time. At some point they'll be back with another new series, even if it doesn't happen for a few years.
As far as the comics go, I think they're not selling well because I don't think under a mainstream publisher, but I don't know because I can't FIND the series in the comic book shops I go to. If the TMNT licence were to revert back to Archie (Where Sonic's series is STILL going strong a good 14 years after the show it was based on got cancelled), IDW (They seem to be putting out niche titles like Angel and Galaxy Quest), or even Marvel, TMNT might fare better.
Give the Turtles time. At some point they'll be back with another new series, even if it doesn't happen for a few years.
As far as the comics go, I think they're not selling well because I don't think under a mainstream publisher, but I don't know because I can't FIND the series in the comic book shops I go to. If the TMNT licence were to revert back to Archie (Where Sonic's series is STILL going strong a good 14 years after the show it was based on got cancelled), IDW (They seem to be putting out niche titles like Angel and Galaxy Quest), or even Marvel, TMNT might fare better.