Let's say I'm a different landlord. If the other landlords are raising their rents, I know that by not raising mine, I can attract more tenants and increase my occupancy rate. Maybe I'm at 70%, and I need 80% to cover my costs. I know that if I raised my rents by $1,000/month, I would lose tenants to the landlords who didn't.
Maybe if you're a landlord in an empty town. But if you're a landlord operating at 70% occupancy, then you're not in a major city of most advanced economies. Cities have demand-driven pricing. 80% of Americans live in an urban area, according to the Census Bureau. There is constant and ever-growing demand, so there is no downward pricing pressure in cities -- Corona aside. I, as a landlord, can take any price the income levels will bear. That is why urban incomes and housing costs must, in tandem, rise unbounded.