You can't fix stupid

Incompetence seems to be so prevalent in my dealings with the marketplace.  

Scenario:

A single mother works at a job, shows up every day and pays her bills timely.  She has a customer who befriended her who makes so much money he will not spend it all in his lifetime.  They talk one day, and the single mom mentions that her 11-year-old car is in need of repairs (again) and she needs to buy a new car.  They talk a little more, and the rich customer told her he would make a call to a dealership that he's bought 7 cars from in the last 4 years.  He said he would tell them to put her in a car.

The mother was naturally excited.  She went to the dealership and talked to the salesman.  The salesman decided he wanted to talk finances before even showing her a car.  Then he asked her to find a co-signer because she had not built up any credit.  The mom has paid cash for everything to this point, so does not have credit built up.  So, the mom tells the salesman she cannot find a co-signer and the salesman loses the deal.

Now I'm thinking what an idiot this salesman is that he would be asked by someone who has bought 7 cars from his dealership and who can take his business anywhere in town and then not fulfill a simple request.  The salesman didn't think this one through very well.  He wants to screen the single mom's finances and then tell the rich customer he can't help her.  That's bad business for a number of reasons:  a dissatisfied frequent and rich customer foremost, insensitive treatment to the single mom, a high stakes gamble if he makes the rich guy mad, and a single mom whose situation will probably improve but who will never return to this particular dealership when it does.  What an idiot!

A car salesman has a number of avenues at his disposal to put someone in a car if he wants to.  His action just shows his haughty and condescending attitude toward others.  He needs to be trained in a hurry by the sales manager before his ineptness costs the dealership a bad reputation among the residents it is in business to serve.  What a complete and total idiot!

Even if the rich guy is not bothered too much by the actions of the salesman, all the observers of this situation will know not to deal with the dealership because of this incident.  I know of 8 people that this situation has affected already.  I don't know how many others, but there are more because people talk to their friends.

Is there a way to eliminate stupid people from a business?!