It's the same problem with the IMC Rating. One is taught certain things but not the real issues in going places.
One could say the same about the PPL for that matter. For some curious reason, this is rarely questioned.
It is possible to get these ratings and come out knowing how to do a real flight from A to B, but it will cost a lot more money because it will involve more flying and a lot of the extra flying will be relatively uneventful. It will be a lot more fun though - just like real flying!
I know pilots who have paid for that sort of IR training but it's rare and I've seen it done only in cases where the pilot was the aircraft owner, the IR was an FAA one, and the instructor was freelancing (probably paid cash; also I don't think one can easily do a JAA IR whole with a freelance instructor). If one is paying school rates, one can easily double the budget if one wants to come out with the ability to fly to real places.
And no flight training outfit wants to double their price list all the way down.
I have no experience of UK airways but I gather that a lot of IR pilots don't bother with them while in UK airspace. It is too much trouble and one often gets shunted around all over the place. So they file IFR flight plans (say going into Europe) which get accepted even though the UK portions are in Class G or D.
Statistically, flying around IMCR-style, below Class A, is just as safe. I've done about 400nm today, 90% under RIS and all outside CAS. Zero hassle; just sitting there with the autopilot and turning the course pointer to the next track at each waypoint.