That said, the price that the manufacturers charge for ink is still outrageous. Yes, it may be technologically complex to formulate a printer ink. However, that's a one-time cost, and economies of scale mean that it's more cost-effective to produce a printer ink in railroad tank car quantities than it is to produce it in demijohn quantities, and it's perfectly possible to design a printhead to feed ink from large bottles outside the printer -- one of the 'continuous flow' systems, generally with 8 fluid ounces of ink in each ink tank mounted away from the print head, so that there is no need to keep the quantity of ink low to improve print head response.
I recently got one of those continuous ink systems for my inkjet, and it works like a charm. For less than it would have cost me to replace all four cartridges with generic ones, I now have an ungodly amount of ink available. And if I ever do manage to run out, I can just refill the reservoirs for less than the system cost me to start with. It works perfectly well for the printing I do, which includes almost no pictures. For pictures I just go get the digital prints turned into real photos, and they'll last much longer than anything I could print at home, even using HP's "premium" inks. (Although I actually have an Epson printer.)
I think what's going on here is that HP is treating this as "everyone wants to print photos", and thus they assume everyone needs super high-quality premium ink. (Or at least that's the argument they're trying to make to justify their ink costs.) But the reality is, most people don't print that many photos, they print out stuff to read, or maybe a cute graphic, or a spreadsheet to reference, and so on. Stuff that doesn't need high quality inks, it just needs to be good enough to read it. And the cheap generic inks you can get for continuous ink systems more than meets those requirements. But HP and company doesn't want you to know that.
Now I've seen suggestions that the ink may eventually cause deterioration of internal parts of the printer, but by the time I run into that problem, I'll have saved enough money from not buying the expensive ink cartridges to buy at least 3-4 printers to replace it with. Even if I have to buy a new continuous ink system for the replacement printer, I'll still come out ahead. The printer companies know this, and they really don't want all consumers to find out about it, because then their entire business model (practically give away the printers, charge out the wazoo for the ink) will collapse and they'll be screwed.