The point, like the song, remains the same no matter what one's actual business is
. Sales training is invaluable if one's business is to continue expanding in the sell-heavy world of modern consumerism. People have been conditioned to buy, which makes them harder to sell to: these days, they want the cat's pyjamas as well as the bee's knees, and the best trained sales people have the best chance of winning the business. It might cost a little now, but it will pay for itself in the long run.