Yeah I was going to address this but deleted that part of my comment. Fundamentally I think there are design limitations.

I used to work in IT at a public school district 15 years ago where they had hundreds of Epson printers with fixed printheads. This saved costs in the cartridges but the inks(which were designed to produce excellent photographic results) had some substance that caused them to clog up these very microscopic printheads essentially rendering the printheads and thus the printer destroyed. This happened a lot on printers where people would only print once in a blue moon.

Seems like you can have two options: poor quality but thin water based inks. I'd argue Laser had taken that market away from inkjet for good. The other option is hight quality photographic ink that is much thicker and gels up easier. Not to mention the printheads are more delicate due to their finer pitch.

That would require some incredible chemistry and engineering. It's just a fact of life that liquids are volatile substances and not shelf-stable once the seal is broken. Toner is superior because it's an inert solid powder.