If you don't know your product or service extremely well, you're on the way to extinction. When I say you must know your product or service, I don't mean what it is, but what it does and what it means to your prospect. Too many salespeople are still rattling off facts and features and expecting the prospect to uncover the benefit. Product knowledge isn't enough. This training usually consists of reading a catalogue, product brochures, or data sheets.
Salespeople become superfluous when a product or service becomes a commodity.
In the last few years we've seen computers become a commodity, and I expect to see automobiles turn into a commodity before I retire from the sales profession. As soon as the general public knows more about your product than you do, it's in danger of becoming a commodity. The professional salespeople who survive into the next century will be those who bring something more to the sale than a glib tongue and product knowledge. They will provide a value-add of some kind. The value-add may be a service that goes above and beyond the expected.