The 75mph is probably on the flat....hill climbing at 75 might not be possible.
Your 30 second figure is probably time to get from 65 to 75 mph - not a lot of reserve poop at the top end.
Still, I'd love to test drive one....in light traffic.
75 mph on the flat seems about right...roughly same as my one liter Geo Metro...won’t get that up a grade unless there’s a huge magnet at the top. P.S. top speed is more a matter of aerodynamic drag coefficient and power than it is power-to-weight ratio. The latter is important in acceleration.