I don't think art has ever really reached the masses either, in the sense of them owning a valauble work of art, as the sort of pictures sold at Christies, is way out of the ordinary bod's league. Let's be honest it's also way out of our league as well. That said, I agree with all the reasons stated above as to why paintings are considered more desirable to look at, by the majority.
I do concur that the collective pre-conceived image of the average coin collector in this country, is indeed of somewhat eccentric retired gentlemen, dressed in clothing redolent of a more genteel era, which might be offputting to some, especially in the younger age group. That's a pity, because if it really did take off in the UK, it could be huge, given our heritage formed over many centuries. I also agree that the image in the USA is totally different. There it is just accepted as a mainstream hobby which might potentially turn a profit.