Ahahaahaha @ 'voluntary taxes'  

As for op, that's sort of like asking:
Would the mob still know how to reel in the suckers in a world free of restrictions?

my guess would be yes!
they might even do it better!

of course vegas is more than a few gangsters now

I think there would be less suburbs...  
oh and the dancers wouldn't cost a dime

Edit: some people would definitely still be addicted to gambling