There were two shitty, cheap units. The people in the first were forced to move out when a developer bought it, tore it down, and built the luxury unit. They have been homeless/going into debt renting a third slightly-less-shitty third unit. Without the first shitty, cheap unit, the second's competition was that third slightly-less-shitty unit; they raised their prices commensurately.
The well-off person moved into their nice new unit. The poor person's choice is staying in the unit they can't afford, or spending thousands on moving costs to go to a shittier unit that they also can't afford. Oh, and the city "motivated" the luxury unit's development with tax incentives. A larger percentage of the poor person's check is now going toward paying that back.
This is the reality once you get past simple narratives and reconcile with the fact that building tons of luxury units hasn't actually moved the needle.