If someone offers something at price A and the market pays price A, then price A is the correct price.
Additionally, larger companies have far more costs to cover than 3rd party specialists, for example (it's far more expensive to provide support and warranty and conduct R&D and safety testing and chemical testing and certification and environmental support and so on than to just provide relatively low volumes of ink to an existing market.
No doubt we could have lower ink prices, but then hardware prices would go up or support would go down or quality would go down and so on.
If you've read the details of the new PrecisionCore, for example, it's quoting making 2.5B decisions a second regarding ink firing in that technology and it's taken about 7 years to bring that idea to market.
Let's look at it another way. How much does it cost in materials (including electricity and so on) to make a fine art print for sale? How much do good ones sell for? Does everyone rely on a 5% marign? No. You pay (as a consumer) what you think something is worth to you and no more which is why some prints sell for more than others and some printers and ink sell for more than others.
Since you have a choice of alternatives (including different brands, different printing methods, out-sourcing, third-party consumables and other systems), you're hardly being forced to do anything and the cost of the ink and the capital costs of the printer, as always, represent only a portion of the total cost of printing (and in the case of ink, not even the largest portion). As such, I'm not sure you can claim to being ripped off.