That's not entirely true, you can rollback a change on modern switches/routers, either via a rollback command, or with a revert timer (configure terminal revert

That's not entirely true, you can rollback a change on modern switches/routers, either via a rollback command, or with a revert timer (configure terminal revert timer X) (because the new configuration might have made the router unreachable, so you're never sure you'll be able to rollback manually if you're working remotely).