That's simply not true!! Let's look at the list:
- Sliders - started out great - brilliantly, in fact - but was ruined when they wanted greater control in season 3 (because lame rehashes of popular big screen movies will always bring in tons of new viewers... )
- Dollhouse - Another show misunderstood - but not for the same reasons - and it ended a year sooner, with the final season being a different format as I recall too...
- Firefly - aired episodes out of order, which got the audience confused since the show was serialized with events of earlier episodes having future development. Easily the best attempt of anybody to do their take on "Blake's 7" but in a more modernized way (for better and worse... can't believe it's 20 years old now...)
- Doctor Who - had everything Americans wanted: Glossy f/x, big highway chase scenes, numerous fourth wall and post-postmodern/metatextual jokes (that Frankenstein one was so great that they needed a sketch comedy actor to help ensure the audience the scene contained a joke), a big tongue-fightin', saliva-flickin', cooties-spreadin' snog at the end... FOX changed their mind the show despite being the most-taped show of the week, which in hindsight may have been for the best considering how Sliders' third season turned out...
- Almost Human - was recommended to me by a sci-fi aficionado who's generally on the ball with these things (more impressive since he disliked the 2009 Star Trek reboot!)
- VR5 (ahead of its time despite using a trendy/faddish p[ot device)
- Space: Above and Beyond (also way ahead of its time)
Oh wait, come to think of it I think you're absolutely right.
Cynicism or not because we're fans of one or more of those shows that got pulled because they didn't bring in a zillion viewers after 2 weeks or because they didn't understand the format (sci-fi is niche, and at least in Sliders' case a lot of the general audience didn't understand the premise either - to such an embarrassing extent that reviews claimed the movie was promoting issues (rather than exploring them, though I didn't see any actual promoting of them and parallel universe ideas were still ahead of their time.)
If FOX only held out... then again, with masterpieces like 2009's "V" reboot, except that one was largely uninspired, it's hard to blame them too much either...Still, FOX had numerous original creations, of which only "Doctor Who" comes close to being a "reboot" (more a direct continuation and to an audience that tuned out after the strange guy with the big scarf offering candy to everyone left, "V" was a true reimagining/reboot).
Basically, Fox not knowing a good sci-fi series is completely different than a sci-fi series being good. If they don't cancel them way too early, they eff it up and make us wish they had cancelled it.
TBH, I'm glad Fox didn't pick up DW. It would have been cool to get it back several years earlier than we did, but then the Beeb might not have done their own revival at all.