New mobos still have PS/2, especially the higher-end ones.
Edit: don't believe me? https://www.gigabyte.com/Motherboard/Z790-AORUS-TACHYON-rev-...
1 x PS/2 keyboard port
1 x PS/2 mouse portEdit: don't believe me? https://www.gigabyte.com/Motherboard/Z790-AORUS-TACHYON-rev-...
1 x PS/2 keyboard port
1 x PS/2 mouse portHopefully if they ever go away for good someone makes a pcie ps/2 card with proper interrupts (if that is even possible behind abstractions like MSI) rather than converting ps/2 to usb