The consequence of that, as claimed in the article, is that when the old tenant leaves, it often ceases to be a rental property - it's not offered for rent but

The consequence of that, as claimed in the article, is that when the old tenant leaves, it often ceases to be a rental property - it's not offered for rent but put on sale for someone who'll live there as an owner. Already there are half as many spaces available for rent as it was a few years ago, and the number is still shrinking. If this goes on, most of the rental stock will get converted to non-rental and you'll be able to move only if you can get sufficient credit to buy the dwelling.