Fuji
If I am honest you are correct infact the experienced IMCR pilot will be safer flying the enroute sector airways basically because it is a much more safe supervised and controlled invironment than stooging around in the rubbish below.
One downside especially in piston singles is icing at many times of the year climbing and cruising at airway levels.
So I do not disagree with what you are saying! We then come back to who is likely to be flying IFR departures enroute and approaches in IMC.
Hopefully the more experienced and current IMCR pilots.
I also take your point looking back at my own development that it is experience, self learnt by being in situations which stretch your abilities and which you survive.
A lot is becoming so comfortable flying instruments that you can do it while thinking about something completely non aviation related as well as literally operating the aircraft instinctively without a check list.
That then frees the mind to deal with more demanding unknowns if they occur.
the fact is we will have to deal with EASA in future and sadly the IMCR does not exist in EASA land and an IR should be good start and finish of your flight whether thats in the UK or Spain
Actually do you need to fly to that precision and tolerance.
Fuji you soon get shouted at flying airways if you dont
Pace