No, in short term people hoarding apartments will be happy to buy whatever amount of new property built. Probably it will hit people 2, 3 apartments, but not ones with 20+ ones.
If they rent for a partial recovery, then isn't that good as renters get a good deal?
Because they are too lazy?
And look this https://news.ycombinator.com/item?id=26610167
Paying people money to avoid the vacancy tax sounds bizarre, beyond idiotic, but somebody does it, and it's there. They will prefer to pay money rather than bothering flying to Canada every month to collect rent, and making sure that renters keep the apartment pristine.