Difficult to argue for regulation of a private activity which has a long proven record of negligible 3rd party risk... OTOH most GA planes can carry passengers and these passengers can be assumed to have at least some expectation of safety. Tricky...
I don't think any legislation is going to work - because the whole GA scene runs on (mostly) crap hardware and (mostly) crap procedures. One cannot legislate fuel margins of say 30 mins when the plane might fly for 3 hours (full rich; few people are taught to lean) but 99% of the planes have useless fuel gauges and 90% of the punters are not flying with freshly topped-off-to-the-rim tanks but (acting fully in accordance with PPL training methods) are
taking the fuel level from the tech log so they are lucky if they are within half an hour of what they think they have.
The only way to do really accurate fuel management is to have a fuel totaliser e.g.
Shadin. Otherwise, the best one can do is to know accurately the fuel flow at given MP/RPM etc and this can be established only with a test flight; no good reading the POH.