Honeywell FMS systems use AMD29000 to this day, including in new designs, and Honeywell even bought the licenses to operate as fabless manufacturer for it.
The reason is simple - they need stability of parts supply with minimal recertification costs, and in this case it means that by having an already certified cpu (AMD 29k) and full manufacturing line capability for it, they don't have to face issues with vendor deciding to scrap a line (like another popular design, i860, had to deal with) or having to constantly recertify and update for newer parts.
And quite often the computing requirements didn't really grow
The reason is simple - they need stability of parts supply with minimal recertification costs, and in this case it means that by having an already certified cpu (AMD 29k) and full manufacturing line capability for it, they don't have to face issues with vendor deciding to scrap a line (like another popular design, i860, had to deal with) or having to constantly recertify and update for newer parts.
And quite often the computing requirements didn't really grow