so they are on life 4. There are three computing platforms that have been around since 1985 and the other two (Windows PC and IBM z) have kept hardware compatibility over time. Many vendors have tried to migrate customers to new architectures like DEC with PDP-11, VAX, Alpha or Sun with 68k and SPARC but few vendors survived the great 68k and Itanium rug pulls.
Actually Apple did
so they are on life 4. There are three computing platforms that have been around since 1985 and the other two (Windows PC and IBM z) have kept hardware compatibility over time. Many vendors have tried to migrate customers to new architectures like DEC with PDP-11, VAX, Alpha or Sun with 68k and SPARC but few vendors survived the great 68k and Itanium rug pulls.