I think you could do a salary reboot without a full product reboot simply by recasting. One of the best remarks about STP2 that I read was a quote by (I thik it was James) about how many people had played Willy Loman.
Why is it that a new production of an old play is called a revival and not a reboot? Because they don't try to reinvent the wheel. Look at the Early Batman movies. All more or less in continuity with each other, three different actors playing the title role. Multiple directors. As much as there are allot of complaints about them none of them were looked upon as a reboot of the earlier ones. Michael Keaton says he does not want to do another one, no problem bring in Val Kilmner.
I get that JJ's first movie was supposed to be the story of ST:TOS in the beginning, how all the characters met. The nature of this concept requires younger actors. It did not however require blowing up Vulcan, Making the Enterprise atmospheric, having Spoke hook up with Uhura (or anyone else for that matter). This is what I do not like about reboots, they seem to mostly be done by people who think the original was broken and needed fixing.
Could Starsky and Hutch have been done without it being a comedy? Could the Brady Bunch been made without them being a 70's family in a 90's world? Could Superman Return without being the messiah? The answer to all of these is yes. What if Star Trek:90210 had been made faithful to the original, so that someone coming in new to the genre could seek out other shows and movies that continue the tale of their new found favorite characters? How cool would that have been?