What makes you so sure they haven't?
There's every possibility that they did contact media outlets but no-one bothered to run a story on them because they haven't really said anything worth reporting--yes, they exist and they intend to bring new games to Steam every month but a lot of people simply don't care about this service and won't care until Gamepump starts being more forthcoming about the games they have in the pipeline and the games they're pursuing more generally.
The only people who are going to give them money upfront without knowing what they're paying for are maniacs who are projecting their specific wants onto a company that may very well deliver something entirely different.
Or just willing to take a gamble if they can spare the 20$ over a year.
I took a gamble and I'm fine with it, even if I'm sure the service is going to be of very little benefit in the end.