That’s a terrible story you tell where not one JW showed up.
I have a theory on this kind of stupidity. Because Witnesses are closed off from associating with “worldly people”, they do not know how to conduct themselves or what is socially acceptable. They are painfully ignorant about many things, in addition to being fools and ingrates.
They also feel there is no accountability for what they do and since you are/were their “brother”, you should overlook and forget it.
I think this scenario is less likely to happen with so-called worldly people. Maybe you’d get one person who forgot about an invitation. But, everybody?