From everything I've heard about it, the Jaz drive was an unmitigated failure caused by bad hardware choices (basically, the "disk" contained hard drive platters and the drive contained the rest of the hard drive mechanism, and you'd insert the one into the other!!). It was also much too expensive.

If they'd never embarked on that ill-fated idea, and instead continue to put all of their wood behind zip drives (and maintaining compatibility), they could've done better. I agree that licensing would've helped a lot. The zip disks were simply too expensive, and they always felt like a proprietary format in a way that 3.5" floppies did not. I was only a teenager at the time but even I was thinking "So wait, this one company is the only manufacturer? Seems niche, not the guaranteed next thing."