That’s just not how housing works. A unit of housing has to be vacant between residents to be repaired, and periodically updated. Leasing a full building often takes a full year. People have existing leases and mortgages. At time you may have a mismatch between types and locations of units and what people looking for housing need. There are all kinds of reasons a unit can be temporarily empty.

The 16k units you’re citing won’t stay empty for long, but other units in the system will go temporarily unfilled. This is necessary for a functional housing market. In order for prices to decline you need a vacancy rate of more than 5%. Prices will continue to rise even at 4% vacancy.

The economics here are well studied and well established. Housing economists broadly agree.

If there’s anything that markers are great at doing, it’s producing lots of stuff at decreasing marginal cost. Housing is no different.

How many vacant homes is the right number? If there are very few vacant homes, then every time someone needs to move homes, they have to be shuffling homes with someone else. That's not efficient or tenable.

Your math is wrong. It’s 2.6% of total properties, not 2.6% of total population.