Of course, with a gearing change it could go a lot faster (it's got plenty of power for it). It's just I imagined they would have geared it from the factory to go faster. Perhaps I am wrong and 68mph is enough for racing and the gearing is ideal. Makes me wonder though why a racing gas dirt bike would be geared to go so fast, it's not like they'd have a need to be cruising on the highway at low revs in the top gear.
Regarding the life span, I had a little look at what's typical for gas bikes and got numbers in the 300-500 hour range and the determining factor seems to be the engine, so stuff like the frame, swingarm, suspension, etc. on the Stark should be good for more than those 500 hours. So that would suggest that it's something in the powertrain that they're expecting to give out, either the motor/gearbox or the battery. That really surprises me. Also a lot of Stark's spiel is focussed on the eco aspect and how it's not polluting like a gas bike, yet they're also saying you should expect to be dumping the battery into a landfill in 5 to 10 years.