All good points. And as @markimiller suggests, IF this is the dealer in question, he might be an old burnt out purveyor of audio hardware that's ready to trade in his surplus gear for a golf cart.
My intent is not to win (or, lose) an argument here but, rather, inject a viewpoint based on decades of experience for consideration. I mentioned in an earlier post that it is unfortunate that the dealer missed an opportunity for a face-to-face with this (potential) customer. It could have paid off for both of them?
My approach to potential customers was one where neither party was over-leveraged, or under-leveraged. This seemed to work out well for me, and my customers. Your example of a job interview does fit into the dynamic. The dealer's career objectives (both short term and long term) does depend on the outcome(s). The dealer's career is enhanced (or, diminished) by what is about to happen so, yes, he does have a vested interest in who is is "interviewing". In this regard, whether we're aware of it our not, everyone we do business with (where there is a lot at stake) is going thru a mental checklist to see if they really want to do business with us. Our portfolio included providing technology, home theater, distributed audio, etc. and using your contractor example, we were given the advice that if the customer/client is badmouthing the other trades on the job, it's probably best to bow out of the project. They aren't going to like you, either. And we may be unintentionally communicating the wrong messages to the dealer, contractor, etc. and disqualify ourselves before we even get started. Probably the best outcome, for all concerned.
In my career, I had to look under every rock to discover business opportunities and was never in a position to pick and choose only elite customers/clients. But I'll say, looking back, after 70+ hour average work weeks, I should have had a better filter on whom I did business with. I missed a lot of life and living. But, I did offer an extraordinary level of service. Wonder if that will be included in my o'bit?