Culturally, bike clubs did not originally exist to be criminal empires. They were just into a different lifestyle. Then throughout the 60s, some clubs grew to many chapters. Once drug culture came in, they were ripe to be hijacked because they had existing pipelines.

Plus you have to consider the rank and file. In the 60s and 70s these guys were beating up prospects, sometimes dumping piss on them, tug o wars where the loser gets pulled into a shit pit. I mean, you can only organize guys like this so much. Their interests only go so far. It was and still often is sex, drugs and violence in no particular order.

Yes guys have organized mini empires and had their runs, but they're surrounded by drugged out fuck ups. It can only go so far before it implodes. And on top of that a LOT just aren't criminals and don't really have any interest in that stuff.