That would require collusion between landlords. Otherwise one landlords rent hike of $800 would be countered by another one who is only raising the rent by $75

That would require collusion between landlords. Otherwise one landlords rent hike of $800 would be countered by another one who is only raising the rent by $750 ... etc until you get back to logical market pricing. Yes some landlords would definitely try it, but I think they'd be quickly corrected by the market.