In respect of the first discussion I think we may be at cross purposes. Touring is more than possible without an IMCR or IR. However proper touring requires a different mind set and a reasonable understanding of the weather. If you do enough VFR touring you will get use to flying low on occasions and you will certainly get use to working around weather or adjusting your plans to allow for the weather. You will also get use to delaying your departure on occasions. It is surprising that in the Summer there are really very few days you cant fly BUT you sometimes have to wait to find a suitable gap in the weather. On the other hand with an instrument rating you are far more likely to complete a given sector of your tour without the same regard to the weather or diverting in terms of time or route from your plans.
In respect of the decline in pilots pursuing an IMCR without doubt the rating has been poorly “sold” by the schools, authorities and representative bodies in recent times. I think this is a great shame as I am convinced a pilot is far better off with an IMCR than without.
I have no idea how much illegal IMC flying takes place in aircraft that are not for whatever reason certified for flight in instrument conditions. I do however know that many VLA aircraft are more than adequately equipped for some types of instrument operations and I would be surprised if some of their members do not on occasions fly on panel to transition through cloud. I am however convinced that flight in instrument conditions (to some degree) by pilots without a current instrument qualification is not that rare, particularly by those with a lapsed rating of one description or another.
It would also be interesting to see how the number of instructors qualified to teach the IMC rating has changed over the same time span? My perception is that there are far fewer around than there use to be.