I think half the problem is that large capacity v-twins aren't anywhere near as easy to ride as an IL4, the brutal low down grunt can be quite intimidating to an inexperienced rider, which an awful lot of colour-co-ordinated weekend warriors are - however if it says Ducati on the tank then they're prepared to put up with it (sorry Peter
).
Then add in the fact that Suzuki made it look so
dull that aspiring litre riders didn't give it more than a second glance, and you have poor sales. The TL had "attitude" written all over it, pity it was such a flawed motorcycle.
.