Not surprised they didn't see other as once on short final you tend to focus on the landing spot until the flare and look up the runway and get a nasty surprise
I was once doing circuits and witnessed the a/c ahead come quite close on rollout to another a/c that had landed in the opposite direction. Heard nothing on the radio.
Now for the power types suddenly faced with an opposite landing glider: The rollout is maybe 50 yards and can be less; so if you can stop on the first half of the runway there will be no problems.
If the glider pilot comes from a busy field, he/she will have been schooled to get the glider
off the runway ASAP. It's not hard to do; pick up the tail to swing it around; then push or pull. The glider won't go straight without help, but you can move about even a two-seater single-handed.