Seems to me (and they never ask me!) that SCCA could simply declare H Stock "ineligible for National competition" if H Stock fails to meet their attendance requirements. In that way the Class is maintained Nationally, and would have some chance at coming back. The same action could be applied to every Class not meeting their attendance mandates. Don't do away with any such class, just make it ineligible for Nationals that year.
If H Stock is absorbed into G Stock, it will be gone forever, despite what some of the posters suggest is possible (for local Regions to maintain H Stock on their own).
2006 Mazda 3S Sport - Making it the best that it can be