I would answer that with a resounding yes! You just need to watch mainstream news closely for a while and pay attention to what they do NOT talk about, or if they finally do, how they do it.
Fact is that all mainstream media boils down to half a handful of very, very, very powerful companies and corporations, and every journalist working for them has to cater to the interests they have or he's soon without a job. As soon as you have a corporation at the top that has close ties to all kinds of other powerful corporations and institutions, independence is extremely hard to maintain.
In my book, mainstream media has lost its credibility long ago, and it does nothing to win it back.