Obsolescence comes when Apple conveniently "optimizes" a new architecture in the OS for a new chip... that conveniently, ironically, somehow severely de-optimizes things for the old chips... and suddenly that shiny new OS feels slow and sluggish and clunky and "damn I need to upgrade my computer!." They'll whitewash it not as planned obsolescence but optimization for new products. Doesn't have to be that way, shouldn't be that way, but its incredibly profitable.
Maybe by that time ARM linux on this platform will be excellent and we can migrate to it for old gear. I still have a 2011 MBP running Linux on my electronics workbench and it is just fine.
