Comment by dijit

I think the reasoning is incomplete.

RAM isn't the only reason to upgrade. CPU's are more efficient, screens are significantly better and support variable-refresh-rates (and high refresh rates), battery technology has not stood still: even if they didn't degrade over 10 years.

There's plenty of reasons to upgrade to a new system even if it has the same memory capacity on paper. The memory will probably be faster and lower voltage too.