I am more worried about the police, and prison lobbies than big pharma. Everyone gets all hung up on "big pharma" forgetting there are other industries and people making a lot of money from pot prohibition, and the war on drugs in general. Law enforcement (The entire industry, from the prison companies, to the uniform manufacturers) especially stands to lose a ton of money if cannabis is legalized.
The MMJ movement IMO has set back the legalization movement. Not only are recreationalists, who comprise the vast majority of cannabis consumers, forgotten about, but people are so focused on the medicinal scene they forget about the other groups who try to keep MJ illegal. My guess is that Obama has little to do with these crackdowns other than to look at the DEA and say "red light" or "green light" to their general activities. No, this crap is coming from the 4 US attorneys here in CA and the DEA higher ups. Also, don't forget that to the feds this is also an issue of possibly losing federal control and power to the states. And that is something they don't want to happen.
As for Harborside, well you knew it was going to happen. You don't go on TV and flip off federal authorities like the DEA or the justice department without repercussions. They are shutting down smaller dispensaries every day, there was no way they were letting the "worlds largest" dispensary slide by. It was only a matter of time.