I personally wouldn't make any parallel between the Turbo and Jaguar. During the dawn of 16 bit, the decision between Genesis or Turbo was a tough one...heck, I remember the Turbo just having more (good) games to begin with, but the future of the Genesis seemed more promising (even with Turbo CD on the horizon). Hardware wise, it was close, with each system having its own strengths and weaknesses, but being somewhat comparable.
All of my serious gamer friends at the time wanted one as well, so if we had been rich, we would've gotten both. Being poor teenagers, you had to make those choices... Anyway, Sega won that battle due to already having some brand recognition and once sports games with big names started to come out( and later, with Sonic and SNES). It wasn't due to bad hardware, lack of killer apps, complete gamer apathy, etc.
Basically, even with the modest sales numbers, the Turbo wasn't a complete failure in the West. It was the victim of a much smaller user base of serious gamers having to make decisions in order to move to next gen. Younger kids stayed with Nintendo, while most older kids/adults decided to go with Sega (or hold on for SNES).
The Jaguar came out and immediately seemed like a step down from all other next gen systems, either already out or in the pipeline. Even at the cheaper price, it was obvious that it was going to fail. No killer app, no software that showed off the hardware, an unappealing, backward thinking controller, lack of 3rd party support and excitement. You name an area, and the Jaguar was underwhelming in that front.
The Jaguar might be cool if you like esoteric consoles, might have a lot of untapped potential, heck, it might have some good games and we should all add it to our collections. But it was a failure, perhaps one of the biggest in console history. The Turbo, besides having underwhelming sales numbers in the US, was not a failure in any way, shape or form.