Landlords in a free market will usually act to maximise longer term profit not rent. Increasing rent in the short term by too much (even if the resultant rent i

Landlords in a free market will usually act to maximise longer term profit not rent. Increasing rent in the short term by too much (even if the resultant rent is below market) only to see a tenant leaving soon afterwards can be a net loss due to void periods and the costs of finding a new tenant etc. Eventually the gap to market rent may grow to the point where the risk is worth it and then an increase makes sense. In the presence of a cap this strategy becomes riskier so it forces landlords to think about a shorter term horizon. There's also a signalling effect of the cap which may mean tenant reactions to an increase at the cap are different.