It's ironic to mention the commerciality of various media. The Guardian for example is a leading left-leaning newspaper and you have to pay to read their articles, talk about accessibility! It seems to me that the more right leaning media is more popular not because of influence but because more people are interested in their content, and often that content is not political.
Let's face it, nobody wants to read relentless political shite, I certainly don't turn to certain media to try and find the latest on political issues. For example, I think the Palestine issue is somewhat important but I'm not going to read about it every single day and certainly most people won't read anything about it.
The mistake that the left continually makes is that they believe everything is a political campaign where all they need to do is take everyone on a journey of enlightenment. However that is alienating to most people who have to work for a living and for example aren't going to care so much to glue themselves to roads or go on protests.