One of the things that always seems to happen with these discussions is that people go to the extremes of what is possible/impossible.
IO540 is right that very few if any Permit owners are likely to want to spend the money to equip their aircraft to fly IFR in airways, as he does. Most don't hold an IR, for a start.
But there are plenty who have very capable Permit aircraft which could easily be well enough equipped to fly through a cloud layer in uncontrolled airspace, or at night.
There is a (necessarily) slow but steady campaign to move the CAA in that direction - sort of an aircraft equivalent of the IMCR. It is a fact that exactly similar aircraft have been flying around in IMC in other countries for years with no greater danger to anyone than for the equivalent Certified types.