And as someone who moved countries a couple of times I have always, obviously, encouraged them to travel.
And, as I said, if they moved away for more opportunities I'd be delighted for them.
One of them will almost certainly be doing fly in fly out work next year and will earn a fortune doing that. Couldn't be happier for him. Obviously I will miss his weekly visit, but his happiness makes me happy and he comes for dinner because he passes fairly close to my house on his way home from work and CHOOSES to visit.
The other one can't come on Christmas days because of work, so we just work around that and see them the following week, no point in demanding things tht can't happen or that they don't want.
They are doing great and wherever life may take them that's what matters.
They CHOOSE to make time for me, I would never whine about it, I raised them to have wings and fly and have a great life.
So yeah, the problem is either you have two very selfish kids, or you are the problem.
Maybe get a hobby and stop nagging them.