The IMCR syllabus is not as closely controlled as the PPL
I know some accuse me of being overly negative on this subject, but I think that people concentrate overly on the "insufficient" IMCR training while IMHO (and working on the assumption that the pilot actually wants to fly for real) PPL training is just as crap.
But in the PPL this is acceptable. It is accepted within the training industry that most PPLs will never be seen again, so why bother to teach them stuff they need to know for actually going somewhere.
Yet the IMCR attracts extra attention - perhaps because IR holders don't like the fact that an IMCR holder has for most GA purposes (non-deiced SEP etc) the same privileges. Especially given the poor availability of rentable planes that are legal for IFR in CAS.
What stops the great majority of IMCR holders flying all over the place and fully exercising their privileges is the same thing which IMHO stops most PPL holders from doing the same: lack of money and lack of aircraft of adequate quality and equipment.
If every new IMCR pilot went flying x/country 100hrs/year to their full privileges there would be a lot more accidents.
If every new PPL pilot went flying x/country 100hrs/year to their full privileges there would also be a lot more accidents, but they would attract a lot less patronising comment from the "old chaps" in this business, because "everybody knows" that the PPL is "a license to learn" etc etc.
In reality if one was training to fly somebody one cares about, and they wanted to fly for real rather than a little local bimble on sunny days, one would go way past the PPL. Even if the pilot wanted only VFR privileges (not very useful for x/country in the UK) one would still need to include substantial instrument skills (flight, and an ILS at least) for basic safety.
Presently, having got the training (PPL or IMCR) one is out there very much alone, and one has to learn as one goes along.