The irony of it all is the same people that designed and make the beaglebone black at $78 are the same people making the IC's in  late model pinbals...
Texas Instruments,so the same argument can be used in 10yrs time about obsolete parts.There are already parts no longer produced that have been used in the Stern Sam system,also custom PIC's on Whitestar and Sam systems.

Chips are made for many years, and yes eventually become obsolete too.  But boards made for a general market become obsolete much faster, to keep up with competition.

All the manufacture needs to do to stuff things up is do a simple improvement like change put all the connectors on a different side, and suddenly all you cables don't reach!  There are many 'improvements' a supplier can do that require the pinball manufacture to do a redesign.  The three USB ports that you use, might get cut to two.  The Standard Definition output might go to UHD, requiring you to do more with the software that now means the processor is to slow.  The list goes on.  ...risk, risk, risk.