Youtube interrupted the video with an ad for me exactly at that timestamp, airplanes still need to catch up. So much monetization left on the table. Pilots must be among the most valuable target audience.
Hence A320 still running on Motorola 68000 of Sega Genesis etc fame.
And 737max having a top panel from the 60s.
You could even insert ads into the recordings to reach the people who listen to the recordings after an accident!
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