Mopeds are deliberately hobbled (for regulatory reasons) so they typically generate less than two hp. Two hp is not the maximum power output of a 50cc engine!
Scooters, which aren't limited by the same regulations (most places consider them "motorcycles"). They can be engineered to attain much better output.
We just have to get used to having less power than a typical chainsaw/lawnmower/weedwacker.