Fat cats and greedy humans are two different monsters. That being said..
Of course they care. Tobacco is smoked and so is mj. There are many similarities in business and interests. You don't think that mj will affect tobacco sales? Of course it will.
Tobacco companies want to get into this industry. They will buy out the small companies and reduce competition while gaining an advantage.
During the Internet and tech boom lots of buyouts occurred and lots of companies went under simply because they were just too small or disadvantaged