hmmm, my situations a bit different in that I had 3 living granparents at birth but all sadly passed away before I was 6. SO I remember their image but their person IYKWIM?

I don't know if I missed out because I have no experience with them, but my parents always talk of them fondly.
As for my own kids, we have lived quite a distance from their grandparents (our parents) since DD was really little. We make sure we talk about them and the kids talk on the phone often. Now we have Skype etc it's much easier and they and we visit as often as we can. I do worry that our next move will be detrimental to the kids for the reasons you mentioned, modern technology does bridge the gap a bit.