I'm not familiar with whats involved in working up an estimate for a boiler.
While you may be correct in your deduction they are looking for "suckers" I could think of reasons why they might have decided not to work up an estimate without the reason being to find "suckers"
maybe he was just lazy. He was supposed to do a manual J heat loss calculator to come up with a correctly sized boiler for the place. I think I might've mentioned going with the company that can give me the best value one too many times. He picked up on that I am cheap and most likely can't afford their prices. who knows.