How is it lucrative?
Would a pad mapper intentionally make some listings bad in order to reduce effective supply?
Because you can use your position to promote expensive listings with more profit. A truly functional aggregator would lower prices by creating efficiencies. It's more profitable to let the market utilize price discrimination as long as the favor is to the supply side. If there is an oversupply then the aggregator would work to raise prices and would be more profitable. Right now the most profitable renter favoring model would be an aggregator that charges renters a fee. The problem is the same people don't rent frequently enough so customer acquisition costs would likely be too high.
Similar how truecar pisses off the dealers and had to stop offering useful info that lowered prices
Everyone that attempts to address the housing market just winds up realizing how lucrative it is to not fix it
Once they get a little data and hire some agents its just a reversion to the mean