For now the BCI-6 continues on. As many are aware, there are fewer and fewer of these machines still functioning...even Canon has ceased replacement parts for these for a number of years. Grandad even asked that I inform him of any cessation ahead of time a couple years ago as he anticipated a move even back then. But for now, I still stock it and continue to get stock regularly.
I imagine any old formulation can be revived as long as a dealer is willing to pay for it as a custom build and it is treated as a custom ink at that point...this means it will be more costly and the complete batch must be purchased at once and that means several gallons at a time. If the ink hardly has sales, no dealer would be willing to do that. However if everyone purchases ink for that machine from a particular dealer, then it may make economic sense for that dealer.
I imagine any old formulation can be revived as long as a dealer is willing to pay for it as a custom build and it is treated as a custom ink at that point...this means it will be more costly and the complete batch must be purchased at once and that means several gallons at a time. If the ink hardly has sales, no dealer would be willing to do that. However if everyone purchases ink for that machine from a particular dealer, then it may make economic sense for that dealer.