One of the interesting bits of information that came out of Microsoft's acquisition of Github was that at the time, the majority of Github's revenue was enterprise deals. Enterprise is a code word that product businesses frequently use for services - yeah sure you have a product, but here are these guys who want to use it to the tune of $10M/year but you will need to do custom development just for them, so what is that? That looks a lot like a conventional service business running inside the same company as your product business.

Microsoft actually seems to specialize in that sort of thing (selling a software product, and then offering some quite expensive, bespoke enterprise consulting services for it). But they are not the only ones, looks around the industry and you'll see it everywhere.

The only real drawback to this model when you're small is that it dilutes your focus and multiplies complexity and cost because you have to manage multiple very different lines of business simultaneously. But if you can overcome those challenges it can make a lot of sense, be an expert at a particular problem, sell a product for the average Joes who have that problem, do bespoke consulting services for the money-laden enterprises who have their own complex versions of it.