The broker/buyer conflict of interest in real estate is exactly what we're working on at Open Listings [1]. It's interesting to think about whether a flat-fee model like ours could work in domain brokering. It's kind of an interesting thought experiment to consider what kind of input you'd need for a program to do the buy-side negotiation.

[1]: https://www.openlistings.co

Edit: Not trying to undermine this domain broker's business at all! He's obviously doing an amazing job hustling for his clients and there's no better option if you really want a domain.