> It seems that they're willing to let vacancies happen instead of lower rent rates

Anecdotally (as well), no small-time landlord I know wants vacancies over accepting lower rents. Almost all of them, however, would prefer a vacancy over getting a problem tenant who will be late in rent, not pay at all, or trash the place. This effect is especially strong in places with strong tenant protection laws.

Professional management companies of big apartments might be different.