All property owners can increase rental prices now anyway. They can only increase them to the maximum someone will pay for it. That's why average rental prices tends to track average income. If you have 5 homes and 6 people, each able to pay 2100, 2200... 2600, then the worst home will rent for 2200, and the one who can only afford 2100 will live in a box.
There's a difference between can and must. A LOT of landlords don't maximally squeeze their tenants.
In fact, I'd argue the majority of landlords are shit investors sat on fairly low yields