> I am assuming that if the increases in cost were not passed onto renters, they would be absorbed by the landlords themselves, which harms the landlords' profit margins. What incentive would landlords have to willfully cut into their profit margins vs. passing the increases on to the renters?
They're not doing it willfully. They're doing it because they have no choice. Let's say the current average rent in Seattle is $1,500/month. Why $1,500, and not $2,000/month? Why are the landlords willfully cutting into their profit margins by not increasing rent? We both know the answer: because the current price is based on what the market can bear; in other words, it's based on the relationship between supply and demand. They can't arbitrarily decide to raise rents without risking losing tenants and having units go unoccupied.
Now, let's say the property tax increases a bit. Will that be passed onto the tenants? Well, can the market bear it? If no, then it won't be passed on. If yes, then why wasn't the rent increased before?
Like I said before, it's different in low cost of living areas. There, the profit margin on top of the costs is relatively small. The rents in that case aren't really based on demand, because supply in those areas tends to be very flexible, you can always make more housing to match demand. For a property tax increase in those areas, the costs will be passed onto the renters, because the primary determinant of rental prices is cost.