It’s a well known fact that as property value rises the yield on rental income decreases.
A $180k townhouse can rent for $1600/mo but a $1.8m McMansion isn’t going to rent for $16,000/mo.
The economics of this has to do with marginal utility mainly and nothing to do with exploitation.
There’s also the calculation of fixed rental costs which derive a larger portion of the monthly payment the lower the payment gets. If management costs are $100 per month that’s 10% of a $1,000/mo rent.
Finally, there are costs like interviewing, turnover, payment risk, eviction risk, legal costs, damage exceeding security deposit risk, and trying to factor this in can dwarf the underlying carrying cost of the property. Some of these are likely to be inversely correlated with property value.