From memory the number of PPLs is around 30,000.
The CAA issue approximately 500 IMCs per year - so that would suggest there are around 1000 current at any time.
(They also issue around 40 IRs per year -presumably to dedicated PPLs or those going on to do an ATPL).
If you check the CAA's reports on progress against AAIB recommendations you will see something like 7 years worth of 'well there are going to be new European licencing rules.....' etc. This was followed up in 2001 or 2 by the CAA meeting with GAAC, reviewing the situation and then stating there was not a problem with the IMC rating content. Unfortunately it did not address the issues raised by the AAIB on accidents that occurred to PPLs with IMCs crashing in IMC.
Hence you now get the policy on IMC ratings that it is not intended for serious use in IMC, it is simply to allow a PPL to make an approach to airfields in conditions that they might otherwise not be able to (????????).
The AAIB's recommendation was for the IMC rating flying content to more closely approach that of the full IR, which largely makes some sense (but only if you leave out all the nonsense theoretical content from JAR and actually make it look like an FAA IR). But it isn't going to happen because of NIH and JAR and now EASA.
If you work at it there is no reason that with good experience built on an IMC you should be safe enough.
But the vast majority of PPLs do not fly IFR from one month to the next. It's expensive and often unnecessary, so they don't get that experience or the currency and that is what makes it a rating to get you into trouble. If the initial skill level were higher that might help - but somehow I doubt it.
As for a PPL not being a high enough standard for flying in the UK. Well that is another issue and a can of worms I would prefer not to open very far. But it stems from the same route - flying is expensive, most people have to ration the amount they do. If the amount they do does n't interest them or is very restricted - yes they give up - much like virtually all the IMC holders.