Ambergold, I think your daughter is in the same sort of denial that I was. I believed visits would be easy, and we could all 'un-emigrate' if we didn't like it. Reality is different. At first you can't afford to come back home, and you don't realise how hard it can be, for various reasons, for parents to visit.
Later, when you could afford to come back home to live, invisible threads hold you - job, new friends, children being settled, and a reluctance to 'fail' or to be seen to have failed.
Visits are lovely of course, when they do happen, but bittersweet. Mum came twice, once when the lads were 2 and 5 and again when they were 5 and 8. After that Dad's stroke-related needs stopped her.
Later still, when you have absorbed, like it or not, the new cultural values, or at least some of them, you start to realise that you no longer belong back home. You may well be thoroughly settled and this doesn't matter.
Your best bet is to impress upon them that if they don't like it, you would understand completely, never judge them for their decisions, and you would help them settle back in any way you could.
The grass isn't greener on the other side - it is simply different.