Power vs Bandwidth.
Want lots of bandwidth? You need lots of "received power", either via high power transmitters or large aperture antennas. DBS satellites (Dish/DirectTV) have large solar arrays/batteries and high power amplifers for their transponders. The video streams are also run on fully saturated transponders, so they can use every bit of power available rather than share it with other transponder users.
Can't generate that much power? You don't get the bandwidth. I've run 45Mbps+ full duplex over a satellite link, but that was using 5m dishes and decent sized amps with full transponders. I've also had to try hard to squeeze 400kbps out of a link using 1.2m dishes + 4w Ku band amps via a shared transponder.