Media companies are businesses. They'd be all over RL if it was pulling the numbers and profitable for them, but it's not particularly, and rarely has been outside of the M62 corridor when they've tried it.
Say what you will about the differences between soccer and RL, and I'm not denying those differences exist BTW, but media, political, and class biases towards RU would have impacted soccer to some degree as well, yet they successfully managed to negotiate it to become by far the most powerful sport in the UK despite that.
I'm not suggesting that RL has any hope of growing as big as soccer, or that it isn't easier said than done, but RL could grow significantly from it's base in England if it had strong leadership, dropped the infighting for cooperation, and implemented a solid long term business plan.
Who knows maybe IMG's influence will lead to those changes, but I highly doubt it unfortunately.