First of all: Outernet doesen’t provide access to the Internet. It only has a downstream (Sending data) and not an upstream.
A arduino would be way to slow for decoding the signal and so on. A raspberrypi has enough power but you would need software and a receiver for that.But i think that there are plans to support raspberrypi or similar in the future.
Having something in stores is also very expensive for a company, sending each unit to the person who bought one over the Internet is much better in my opinion.
Sending the data over a dvbs signal is not ideal and would require more bandwidth (and so will cost much more).