The 128GB version wouldn't be throwaway, since that's the maximum the platform as a whole supports anyway- more memory than that would require a new mainboard and CPU at the same time.
That applies to all computers when you buy the fully specced versions on day 1. A maxxed out iPad isn’t throwaway, but framework represents a higher standard of upgradability.
the platform should support more memory
Not for upgrade reasons but what if you have a fault in one of the dimms or etc? Now you can't just drop in a replacement without changing everything.