The amount of data you can transmit over a radio link is proportional to the span of frequency you use. Your bandwidth. Satellite operators used to have almost all of C band's frequency span. Changes were recently pushed through to give half of this to mobile telcos. So now the satellite operators have to push the same amount of video/media with half the physical resource to do it. So they need to send half the data. The FCC has literally told the incumbent sat users to switch to HEVC to accomplish this.

Frequency gives you available bandwidth. Less bandwidth forces you to compress it more. So you either send worse quality, or compress it better with a newer/better codec.