Yeah, I don't think it's possible for me to disagree more.
If you're seriously going to start talking about the history of the franchise, and you think it's actually wise to use this as an example of how quality doesn't matter, you're disrespecting the creators' feelings on what originally happened with TMNT. They didn't want the cartoon to make as many compromises as it did, and this even included Kevin "I'll Roll Over About Everything Nowadays" Eastman—it's something they wished they could've redone.
What they envisioned for the TMNT cartoon was much like the more critically praised animated series that followed, a la the aforementioned "Batman: The Animated Series," or "Teen Titans," or anything of such respectable quality. Did they cash the checks? Yeah, sure. Shit, I don't blame them for that. I'll roll around on a Goddamn bed of cash just as fast as the next person. Is it what they wanted in the first place? No, and we'll never know if they really would've had a problem selling those figures if they'd pushed for something sincere.
Even so, I wouldn't say that it's strictly nostalgia playing a part—after all, the original TMNT cartoon had some mighty fine voice actors, and that does make a difference. You may have a silly story, and a villain that embodies incompetence, but can you sell it? Can you take that shit and own it? They sure as hell did.
Beyond that, the first TMNT film was more of an homage to the original comics than the cartoon series. It used various staples that the latter pioneered, like unique colors for each of the turtles, and Michelangelo's party dude persona, but it was far more in line with their original vision. The darker concept also meshed well with Jim Henson's Creature Shop and their tendency to produce good fantastical works, like the preceding "The Dark Crystal," or their later work on "Farscape."
Did the movie do well because the cartoon and toys already existed? I think you'd be a fool to say no, and I know you won't, and I don't think anyone else around here will either. No toys were made based on it, though. Additionally, did it stand on its own as a good movie, especially considering what it involved (puppetry) and for the time? Yes, and it's still completely enjoyable to watch today, even if said puppetry might be tougher for modern audiences to accept.
I do believe that a standard was set. Each production demonstrated that you can be straight, or you can be silly, but you can still produce something that can be called "good" at worst. Either it's got your heart in it, or it's got some good actors behind it, or it's got something to prop it up and keep it in the realm of reasonable quality. Before Bay, almost every effort to create something that was truly shit with the TMNT label didn't do well—like the aforementioned third movie, or the musical that barely made it through its first tour before plodding through the second, or the toys that Playmates made out of desperation in the late '90s when the turtles weren't popular (and yes, there was a period where they weren't).
And if you want to do another TMNT movie that's respectful of all that, it's already been done before, so there's a bar there, too.
The new flick is shit. It didn't have to be.