BS”D
Indeed, under any new and viable limited full time or expanded part time system, the future gedolim, dayanim, poskim, roshei yeshivas will be the only ones remaining in koilel until they and a position match each other.
Another alternative is the SEED type kollel where the koilel yungerleit teach and learn at the same time. Service in such a kollel, outside the city, should indeed be subsidized by the community for a certain number of years, depending on the individual avrech (and his teacher wife) and how they perform in that environment as well as how long they feel they can contribute in this manner.
This sounds like a good way to train mechanchim in particular – let them teach whatever they know to those who need to know the basics as they themselves learn more.