Unused features might sell the product

During a Scrum training at my company, there was an interesting discussion between a few people.

As you might know Scrum is based on the Lean thinking, which focuses on producing as little waste as possible. Our Scrum trainer presented a slide showing that 45% of the functionality in a product is never used, which makes it the equivalent of Lean's worst kind of waste: over-production. It should therefor -according to Lean thinking- be eliminated/avoided.

One of the attendees asked: "but what if those 45% contains features that helped sell the product?". Which is a valid question, especially in a market where the buyers of a product are often not the users of that product.

Unfortunately nobody knew a really good answer. The trainers remark that such a feature set was not "sustainable" was true, but irrelevant. Does anyone else have an answer? So what do you do with those features no one uses, but that effectively sell the product? Leave them in without maintenance? Just advertise them without properly implementing them? What do you do?