I know this is a hard ask, but consider the Apple or Lenovo model of long support contracts. Not only does this help a lot of buyers to get your product, but you can start refurbishing trade-ins to get parts to service support cases.
In the Frame.work style you might be able to do it via a more DIY approach.
IBM used to guarantee availability of the exact chips, and did a lot of stuff behind the scenes to make that happen.
That sort of a guarantee way beyond what's reasonable of Frame.work, they don't control their suppliers to that degree. They've already updated the peripheral chips & hardware even within "v1", both for bugs and supply issues.
Frame.work has pretty much implied the form factor will remain largely untouched, so you're likely to be able to swap a component in even years from now, even if it'll be an "accidental upgrade". That sounds quite reasonable to me...
I know your roadmap is probably packed to the brim, but if you could help facilitate 3rd party sales that would be useful. My wife stepped on my framework 3 days (!!) after I finally got it back in the beginning, and you couldn't buy parts yet so I bought a whole new framework and cannibalized it for the screen. I've since repaired it but if there was a way to either trade or sell with other people in a similar boat, that would be amazing, particularly where not all parts are available for purchase at each given time.
