I don't mean band-aid as in there's something wrong with their architectures. They're great but they are 10+ years old.
I mean band-aid in terms of applying all the new things Tesla has learned and developed (4680, mega castings, manufacturing processes, list goes on and on) to an architecture that was designed before any of those things were even ideas.
Don't forget that 4680's don't mean just 4680's. It means structural battery packs and mega castings to get the packaging right (cooling requirements, weight savings, manufacturing efficiency, etc). It's not just a straight battery swap.
S/X are too low volume and old to make that worth it. Better to start with a clean sheet.