Firstly I'm agaisnt second home ownership, but it should be pointed out that the number of second homes is that significant in the context of the whole of the UK. I've seen figures from 80,000 to 350,000 quoted although obviously they are concentrated in particular areas of the country - Cornwall, Devon, North Norfolk, Central London. However they have become a sort of symbol of the discontent caused by often much wider social changes. The huge numbers of long distance commuters, the switch away from agriculture and manufacturing towards office work, a much more mobile population and communities becoming less mixed are far more significant but less visible causes of things like the loss of the post office and young people moving away.