Vegas even tolerates Nicky for while until he really starts to operate outside the set of already crooked lines established by the corrupted officials.
In Casino we are repeatedly told and shown how everyone is in on the scam and no one cares as long as the right palms are greased, ppl hired etc. In Goodfellas we are shown one crew of criminals out to make a buck any way they can.
I think the reason Casino ends up being a much stronger commentary on capitalism in America is that we get to see much more of how the state and national governments were enabling the gangsters.