@shakey jake will be able to explain it alot better then me.I won’t touch wasp nests if they are in the paddocks, only if they are in areas where we go a lot, like the garden / stables.
Wondering if many wasps built ground nests last summer only to then get drowned in the wet winter. Might explain the lack of them this year.
I never had much of an issue with wasps until we started keeping bees and as I said its "upsetting" to see a decent colony destroyed by wasps. However strong colonies of bees will destroy a smaller colony of bees as well..... but in many cases thats much easier to deal with then wasps unless you can find the nest. We have tried all sorts of wasp traps over the years but when they are on a mission its often very difficult to stop them and moving hives is not always easy or practical.
My view , like most things, if its not bothering you or your activities then leave well alone if you wish