A straight calculation based on modern LIPO batteries seems to defy the above logic.
The CT and Eurostar aircraft are within 0.5kg of max empty weight factory built and that is with min allowable kit, no radio and no transponder
I know I keep coming back to this, but do the dealers who sell these clearly state that
- you cannot fly to NORDO airfields (loads of them)
- you cannot fly in transponder airspace (plenty of that too esp. abroad)
Looking at 253kg, saving 5-10kg on that should be easy. There are loads of parts which are not significantly stressed and these could be made of magnesium instead of ally. I machine Mg routinely at home; it's perfectly safe.
Finally, I agree aerobatic planes fly potentially anywhere vertically but they are not a statistically significant bit of the big picture. If they were, they would be introducing a new hazard, but aerobatic pilots generally choose places to do it where there isn't much traffic.