ATSC 3.0 technology will allow for many more channels than ATSC 1.0 as well as:
Greater Capacity. A system can support a third-party “offloading” business where data, video and other bandwidth-intensive content (such as software updates for devices) canbe transmitted over broadcast networks for “edge” storage or delivery to non-household destinations. Today’s wireless service and streaming videoproviders, for example, have acute needs for greater capacity to cost-effectively move their content as close to their customers as possible.
Second Screen. The ability to deliver program related second-screen content by either Over the Air (OTA), or OTT distribution and interactive content.
As for ATSC1.0, unfortunately the sub-channels are not protected by the current proposed rulemaking, only the top 5 networks: ABC, CBS, NBC, FOX and PBS are.
An ideal theoretical model would be collaboration among the five primary network stations in a single market. The Lighthouse Station will have its ATSC 1.0 signal carried by the other partners in the business collaborative. (page 57 version1.1 - Transition and Deployment Guide)