I'm interested in their long term profit potential.  

They're essentially taking over the weed business from drug cartels and organized crime in regions where legalization occurs. Its been estimated the US black market for weed is worth in excess of $50 billion. That could represent an upper tier for earnings growth over the next few decades if it gradually becomes more regulated.

There is also the potential for legal weed to takeover some of the markets enjoyed by big pharma. Things like aspirin and pharmaceutical remedies for many varying medical conditions would eventually be taken over by legalized marijuana.

The industry definitely has potential to sustain high growth.