Rents will go up, as will prices for existing, rentable, houses. So current homeowners benefit at the expense of those who will continue to rent.

I have no opinion on the movement of new housing purchase prices. It depends on the kind of landlords buying houses in Amsterdam, and their alternative investment options; also on the volume of additional demand generated by the increase in rents.

I'm not sure why you believe the Amsterdam rental market to be predatory, or what you even mean by that. Perhaps you have more experience with it.