In defence of the handling agents, sometimes these things happen, and things land late/early and with the best will in the world sometimes you will have unforeseen flights, for a small crew, especially on late shifts
But this is where the problems are. In the "good old days" when you got hit hard with several flights landing at once, you just spread your men out and did what you could to AT LEAST get the passengers off. Everyone could operate the stairs, and put the power on, so 6 men could "greet" all the flights, with at least 1 set of stairs before returning to continue/begin offloads.
However, today the BIGGEST problem is purely down to training. In my days on the ramp, it was something I highlighted over and over again, and I was always ignored. Everyone out on that ramp should be trained to drive/operate as much of the equipment as possible from the very day they start. Training should be ongoing.
I used to go absolutely mental when I was leading a crew, where of 4 lads only 1 could operate stairs, or only one could tow a GPU (but not put it on the aircraft). It was so inflexible it was ridiculous, and if you did get hit with several a/c coming in at once, you did get times when you couldn't get steps on because you didnt have enough TRAINED staff. Instead of 5 lads who could meet the inbounds, and get the stairs on, you effectively had 1 lad who could do it, and delays mount up.
This is probably what happened in the original post. Especially at that time in the night, probably because most of the evening shift had played to the whistle and clocked off bang on finishing time, because the HA were unwilling to make it worth their while to stay for the late inbounds.
"Ramp trainer" at some stations must be the cushiest job ever.
RTG!