When a landlord increases rent by X% they are saying that the value of the property has increased by X%. Unfortunately businesses and landlords got together to push (and pass) prop 13 which amended the CA constitution to prevent assessed property value from increasing at more than 2% per year.

That means any time a landlord increases rent by more than 2% they are benefiting from incorrect taxable valuation. Because property taxes cover the infrastructure that supports homes + buildings (the roads, police, firefighters, teachers, etc) they are directly offloading the costs of those services onto people who don't own property: The people who don't own property then have to (in addition to insane rent increases) pay higher income taxes, in order to support those services the are functionally there to benefit the undertaxed properties.