Not necessarily. Businesses are usually fine with making things worse for themselves if it also impacts all of their competitors, preferably even more. That is, as long as a business comes out a bit more ahead of their competitors, a business is usually just fine with making something worse for everybody.

So, even if a business currently gets a lot of revenue from Facebook, as long as a business thinks that other businesses in their field are more dependent on Facebook than they themselves are, they should be fine with Facebook declining.