This has been going on ever since Cave Girl smartly priced her nicely-decorated cave, leaving the Cave Man down the street cursing picky buyers and bargain hunters!
Here's the thing - Homeowners have a Constitutional Right to Over Value Their Home. Real estate brokers have a right to contract with Sellers Who Insist On Exerting This Right.
Listing Brokers owe their clients Loyalty and Honesty. It is a Violation of Realtor(r) Ethics (this is true) to mislead Sellers as to the value of their home. So "buying" listings is an Ethics Violation.
That said - if everybody else thinks the house is worth $400,000 and the Seller shops for a Broker that will take the Listing at $600,000 - how is this our business?
Now, being as We are all Ethical Brokers, we're going to tell our prospective "Seller" what we think is the truth, right? "Mr Murphy, yeah, you know, houses like yours - look at the comps, three-seventy, four-twenty. At six hundred, people are getting circular driveways with fountains, moats with fully-automated drawbridges, they're not next to gas stations, they have roofs and siding that's more substantial than blue tarps . . . "
So there's really nothing to "overcome." Sometimes, the Seller is delusional. Sometimes, they really don't want to list with you! And, sometimes, you're willing to give it go. So long as you've been straight with the Seller, frankly, I don't see the problem.