I'm curious why no one worked on creating really portable printer (Epson Workforce WF-100 for example) with different ink options, so the printer is really just one time investment and the ink could be just as cheap as it can get. Currently, it seems like an oligarchy where the goal is to sell printers and then keep making money by selling single use cartridges.
On the other hand, the space like 3d printers, or mechanical keyboard is already getting so much 'indie' development. I'd personally love to buy a printer (like my mechanical keyboard) that I can use every once in a while and something that is easily/cheaply refillable.
I suspect you're right about it being mostly a money generation effort.