You'd have to be pretty naive to think being legal would then suddenly mean you can easily make it. Burgers are legal. The vast majority consume them. Now open a burger joint and corner the market! Oh wait.. Health code regulations? Employee benefits? Payrolls? Tax? Inspections? Fire code? Have to be better and/or cheaper then the big chains? Who would have guessed running a successful business wasn't trivial!

People who were in the game before competed against anyone who couldn't run a small time dry cleaning shop. They were in it because it was illegal and those good at business was instead running legal businesses.