A salesperson gets your product in the door. Without that, any potential customers don't know, or care what you are selling, no matter how great you think it is.
This is true if you are unfortunate enough to be operating in a large market with little or no name recognition. The shop I work for quietly sits back and waits for potential clients to contact us. Our client referrals are strong enough to keep our project pipeline running at full capacity year-round.
Totally... but remember that I didn't say that no company ought to have a sales team, I just said I don't want to work anywhere that does. Filtering out B2B companies with products that have frictional switching costs is exactly the purpose of having that kind of a litmus test.