There would be no clearances to overfly available and no separation provided, a mandatory broadcast frequency is more designed for picking up ATC errors rather than having pilots sort out things entirely by themselves.
Overflight charges are easy money and I'm sure the Taliban will want that source of income back asap.
The USA military provided some sort of ATC coverage in Somalia, so possibly having an AWACS deal with high level transit traffic would be possible.
I'm sure airlines overflying Afghanistan have been onto their insurance companies