It might also be question of the association we all have with Startrek and all its cool stuff.
Transporters, Shields, Warp Engines, Vulcans [logical minded people], Klingons [warrior race]
If you made a entirely new series set in a different Universe, but wanted to use several of the base ideas of Startrek, it would feel strange. People might call it a rip-off and dislike it just because it "steals" ideas from Startrek.
It's the same question as with Battlestar Galactica TNS - why do a re-imagination and not set new show They could have called the show "Exodus" and made it about a group of human colonies being overrun by a robotic army and fleeing to find Earth - but who wouldn't have noticed that it's the same basic plot of the original series?
Maybe it would actually be a good idea to re-imagine Startrek, instead of making prequels and having to worry about not messing with the timeline or messing the timeline and getting fans angry, but in the end, no solution is optimal.
Maybe it's time we lose our focus on having only one original version of a universe or show - It worked in other areas (comics reboot, plays are played with different actors or different locations, songs are interpreted by different musicians...) Maybe one reason why it is so hard is because we invest so much more in a series/universe then we do in a single book, play or song...