^Then don't trash them. When they reach the point when further propping up is not economical and possibly damaging to your professional reputation from delivery time and quality issues, give them to somebody else who has the time to deal with the problems.
If you list a dead wide format printer on Craigslist, you will have several replies within minutes, as I did with my 9880. Or offer the dead unit for parts, the catch being that takers have to haul away the whole thing. As organ transplants that hunk of industrial materials can live on for many more years. And much of the steel such as in the base is highly recyclable and of great interest to scavengers.
Let's see, 70 years on my body, 36 years on my refrigerator, 28 years on my house, 12 years on my pickup truck, 3.72 years on my 8300. My goodness how time flies.