Again multiple sources vs you. I believe the multiple sources. Especially when I know first hand you’re just plain wrong about beer. Then there’s this:
http://www.cracked.com/article_19609_5-horrible-things-nobody-tells-you-about-legally-growing-pot.html
And of course in the long run is doesn’t matter. 90% of the service industries in America exist doing stuff we can do for ourselves, but we don’t. So even IF growing and processing pot was easy (which it is not) people would still PAY for somebody else to do it for them. The same as they pay people to cook for them, clean for them, walk their dogs for them, build their furniture for them, do their driving for them, fix their cars for them, and all the myriad other stuff of varying levels of difficulty we opt not to do ourselves.
Do you make your own beer for you and your friends?