If you're a software company and you have only a few customers, then you're probably doing bespoke development (whether you call that consulting or not can be y

If you're a software company and you have only a few customers, then you're probably doing bespoke development (whether you call that consulting or not can be your own decision), not product sales. The entire purpose of selling a product is to scale through volume rather than customization. To me the big divide is how superlinear your revenue:employee ratio is. If it's linear or close to it, then you're a consulting org. You make money based on the hours of work you are able to bill for in one way or another. If it's a "product", but you as the product developer are doing heavy customization, then you've just transitioned from an hourly billing model to something resembling fixed bid, but with a fiction of a product in the mix.