In what way were their interests aligned with yours? (this is not a snarky question. usually in real estate their interest is to make the deal happen asap, which doesn't align fully with your interests)
The deal happening ASAP was aligned with my interests in this case. I would have taken a lower sale price for a faster close.
But even aside from that, they make more money the larger the deal, so they work to get a good price. They also feel the pain if the deal falls through, so they have incentive to keep the deal alive and both sides happy.
The broker isn't perfectly aligned with me, but of everyone else involved like lawyers, accountants, and the buyer, the broker is by far the most aligned with my interests.
GP may be referring to freakonomics. One of the things the authors point out is that it can actually be better for real estate brokers to crank out lots of sales rather than spend a lot of effort finding good deals for the seller.
In real estate brokers typically get around 2.5%, so even if they find a buyer that is ready to pay 100K more, it's only $2500 extra (so probably $1500 after taxes). It's not a lot of money esp if they can invest that time and energy in parallelizing other deals. Time is of the essence in such transactions.
And then of course a Buyer side agent's incentives are aligned exactly opposite to the buyer, but even if they would want to push for an early transaction above anything else.