If DBS sub counts drop drastically yet many in rural areas would still need service then I could see a merger being allowed to stay in business and the government may help subsidize to keep costs down or to keep the business running so that those in rural areas can get the service and local channels in case of emergencies and so forth.
If DBS were to go out of business then there will be other companies running at the chance to serve that market via wireless/powerline/etc technologies to get the business just like wisp's do.