If you're worried you eventually won't be able to find a replacement screen, that same idea still applies to not being able to find the right "analog" instrument cluster 10+ years after the car ended production. Some cars are going to get some really bespoke instrument clusters that only exist for certain years of certain models, while others get the same off the shelf display that automaker has used on a dozen different models of a similar-ish generation. Once again this makes little difference to the instrument cluster being "analog" or a screen. Its not like they're forced to always use the same "analog" cluster currently or that going to screens will force them to make each model bespoke. I do agree, I want automakers to continue to have or keep moving towards repairable/easily sourced parts and dislike when I see movement in the other direction, but arguing they shouldn't use screens is a pretty unrelated issue from what I can tell.
Buying a car with analog needles isn't going to make that part more available if it becomes one of the last models with analog needles. Screens can be pretty standardized.