I had a chance to see some old archives of the GUE website a while ago. Every year since they started listing instructors, they have had sizable turnover with their instructor core. Its really nothing new.
Somehow I suspect there will be a reasonable amount of instructors teaching good tech/cave classes - even if GUE somehow goes away.
Edit:
The first archive I can find with instructor listings is here. That original list has 22 instructors.
Compare that to the list of instructors for the end of 2000 here. In a little over a year and a half, 5 of the original instructors had moved on.
The numbers aren't new, it's the quality.
Since I've followed GUE from pretty much its' inception till now, and I know who has come and who has gone, I can say that it's not about the numbers of those that have come and gone. It's about the quality and distribution. The initial 2 waves of GUE instructors came with a resume that were 2nd to none and taught courses reflecting their experience and were pretty much located where it matters. There was a plethora of Cave and Tech guys to choose from and we knew who they were and what they had done. Check out the courses available and locations of the GUE Cave/Tech instructors that were available in the original list and the ones that are listed now.
The instructors that have come since then have pretty much been all DIRF guys that are pretty much anonymous with not a huge record to stand on.