Who says it has to be fair?
Electricity is not my specialty, but from what I know - RV parks suffer from couple of main things:
1. building codes that assume not too many recipient will pull full power capacity at the same time. That works for stick houses, but not for RV
2. camp builders who don't want to spend money on system that would be able to support 30 amp at each single site when heat wave arrives.
Thank God for generators in most of RV, or during heat wave whole campground would be sitting in dark waiting for transformer replacement.