A lot of these properties apparently are bought by wealthy foreigners purely speculatively, and sit vacant. If they were buying them to rent them out, I'd agree

A lot of these properties apparently are bought by wealthy foreigners purely speculatively, and sit vacant. If they were buying them to rent them out, I'd agree with you, but as it is, they end up reducing the housing stock that's available to be lived in while the number of people stays the same, so they do drive up price.