Here's the difference: Replacing a customer is easier than replacing a client. If you build widget X, but then your customer decides they want Y instead, all you have to do is find one other customer in the world that wants X and you sell to them instead. Whereas in a consulting relationship you tend to have to throw X away and build Y, because hey, you're under contract and the client must be appeased.
(In theory you can write a contract stating that if you build X for a client and they refuse delivery you can repurpose X and sell it to a different client. In practice... consultant-built work product and an actual product are different in so many annoying little ways - assumptions about client's specific workflow and IP baked in, for example -- that this is never as easy as you think, and rarely easy enough to be worthwhile.)
Firing a customer is also easier than firing a client. They buy in little discrete chunks. Just apologize that your product no longer meets their needs and they won't buy the upgrade, or they'll cancel their subscription. In the absolute worst case you'll issue a refund. But compared to the soap-operatic stress-filled lawyeriffic delights of contract negotiation such events are almost a delight.
Here's the difference: Replacing a customer is easier than replacing a client. If you build widget X, but then your customer decides they want Y instead, all you have to do is find one other customer in the world that wants X and you sell to them instead. Whereas in a consulting relationship you tend to have to throw X away and build Y, because hey, you're under contract and the client must be appeased.
(In theory you can write a contract stating that if you build X for a client and they refuse delivery you can repurpose X and sell it to a different client. In practice... consultant-built work product and an actual product are different in so many annoying little ways - assumptions about client's specific workflow and IP baked in, for example -- that this is never as easy as you think, and rarely easy enough to be worthwhile.)
Firing a customer is also easier than firing a client. They buy in little discrete chunks. Just apologize that your product no longer meets their needs and they won't buy the upgrade, or they'll cancel their subscription. In the absolute worst case you'll issue a refund. But compared to the soap-operatic stress-filled lawyeriffic delights of contract negotiation such events are almost a delight.