In doing that work we talked to a number of people in the ink business and learned that the same companies that make the ink for the OEMs often also make ink for the "quality" 3rd party ink market, but they have an agreement with the OEMs not to use the OEM formulation (obviously) or make their own inks "too good". There are sometimes patents involved with the OEM formulations, but it is possible to make good inks without violating active patents.
I know someone who worked on designing a plant for one of the major ink suppliers, and he told me that the manufacturing cost difference between an OEM formulation and in-house formulations is probably less than a dollar per liter (32 ounces). The explanation that the OEM inks have more expensive components and that is why they cost more has more than a little exaggeration involved.
We also inquired about the possibility of adding stabilizers to improve their own ink's longevity. We were told that there are very few people who care about this, and that it wasn't worth the effort. Sadly, I have to agree, as the vast majority of inkjet ink is used in low quality applications or by people who aren't concerned about longevity.
Another point of interest. I have very few complaints about my prints fading, but one daughter had problems with photos taped to her refrigerator. I have worked with electrostatic ozone generating devices in industry, and my nose is attuned to the smell of ozone - I could smell the ozone from their "air purifier". Once I showed her data on the dangers of breathing ozone, she threw the air purifier away. Her fading greatly decreased at the same time. For prints that I want to keep, I print them on swellable paper and frame them behind glass and locate them where they aren't exposed to direct sunlight. I don't see any appreciable fading after several years.
