It is unlikely the dealer would ever have the opportunity to meet Musk. Clients at this level are spread pretty thin and have estate managers and personal assistants that you meet with. That said, even under these circumstances, it is up to the dealer to discuss the client's needs and offer the best possible solutions. Often the client has no idea what his options are and if you do not make the effort to explain to their intermediaries that there are options, the client will never know.
It is obvious that short of making sure the check cleared, there was little discussion. They didn't even realize that a 5.1 system was desired. This is a classic example of very poor performance on the part of the dealer.