Well, you'd originally asked whether it's the customer or inventor's "fault" and pretty much suggested that it was the inventor's. I was, merely indicating that it can go either way, depending on the scenario.
But, yeah, if you further qualify it by saying that the inventor was trying to sell ferret-poop rockets, then that marks a scenario that's pretty clear-cut.
It's no further than my initial statement, it was just clarifying how your quote applied to the situation. The inventor is the one at fault if they envision a product people don't want. That's all. Maybe you can blame their marketing team too.
But, yeah, if you further qualify it by saying that the inventor was trying to sell ferret-poop rockets, then that marks a scenario that's pretty clear-cut.