Serendipitously, the BBC had an article on this very matter.
Whilst second-home owners and retirees were rightly held up as the prime culprits, there was another reason for the lack of ability of local people to find a home in the area mentioned, but not very loudly, this is the BBC after all:
"It is like a perfect storm - there's a lack of social housing, a lack of affordable homes, rising prices, not enough well-paid jobs.
Yes, the Tories' political masterstroke of the 80s, the great sell off at undervalue of the country's social housing, is still having its malign effects to this day.