That's absolutely true, but having many more biased sources than in the past makes a difference. 20 years ago, a majority of people got all their news from the big three and AP. They spent their entire lives hearing the Democrats' point of view, and the Democrats' twisted version of the Republican point of view, and never even recognized any bias because they had no idea the Republican point of view was being so grossly misrepresented. It's very difficult to recognize bias from a source, if the information one could use to determine bias is coming from the same source.
Even today, many people I know, including family, simply have no idea what the Republican point of view is, or why so many people vote for the "party of the rich". They have no interest in researching both sides of the issues, when ignorance is much easier.