Since 2013 I've seen my folks twice - once for 3 weeks when I went back to the UK to get married, and again in 2016 when they came out for Graduation. Seen my in-laws 3 times in that time - they came out in 2013 and 2014.
I think for my parents it's been hard as I'm here and so is my brother, and my brother's got a little lad out here... so they're doing the grandparent by Skype. We had a visit from my brother the other day, and we doubt our parents will do another trip out - in-laws however, will probably be out again.
My parents have been supportive of me being over here, they can see the opportunities here for us compared to back in the UK - and they know how happy we are here. I grew up at least an hours drive from my next nearest family, which is unusual in the UK, but I've come from a family where it's normal to move for work.
My view? Grab it, if you don't, you don't know what you're going to miss out on in both lifestyle and opportunities. As you say, parents can up and move, or come and visit.