"Buttons" sound like a complement to the synthesizer's business. If buttons become super-cheap for their customers, their customers will buy more synthesizers,

"Buttons" sound like a complement to the synthesizer's business. If buttons become super-cheap for their customers, their customers will buy more synthesizers, without the need for the company to maintain any kind of inventory or fulfillment for replacement parts. There is the "sell the razor for free and make up for it on the blades" model that completely doesn't work if customers can print their own blades, but this company doesn't seem to be using that model.