[yencabulator]

PC boot loaders have been able to fall back to previous configurations on boot failure ("automatic redundant OS upgrades") for a long time[1], so that's not a valid excuse.

https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT/

https://www.gnu.org/software/grub/manual/grub/html_node/fall...

https://www.gnu.org/software/grub/manual/legacy/Booting-fall...

[1]: Minimum about 23 years, from personal use in creating a product with A/B-root partitions.