I am all for living near grandparents and wish we did- near my parents. But take off your rose colored glasses first. Ask your siblings if mom and dad actually help. Imagine worst case that you relocate and your parents aren't super involved, your siblings are too busy with their own kids, etc.
We relocated cross country to be about 2 hours from my in laws. We have seen them maybe 6-8 days total in the last year. We have seen my parents 15+ days despite being12 hours away. And that is with my in laws being retired! We never would have guessed given how the in laws whined about never seeing us when we were far away. We are now looking to move back closer to my parents :(
This is a very good comment. We moved back to a very high COL area, with less salary, to be closer to grandparents when my oldest was 9 years. Yes, we missed out on the baby rearing help from 1 year on (both MILs stayed with us alternating the first year), but it was well supplemented with local friends with kids at the same age, so minor impact for the first few years.
As the kids grew into preschool then elementary, we realized that they were missing relationships with more adults who loved and supported their good choices and values.
However, when we moved, we decided instead of buying a home in the area we wanted, if we were moving to be closer to family, we needed to be CLOSE to family, and chose a place 10 minute drive away. That made all the difference, I am certain we would only see them 1-2 times per month if we lived 1 hour away.
We also gained help on "sick days", and taking kids to / from activities at least once a week.
This decision put us back from FIRE for at least 10 years, so my kids have only had a SAHD, but no opportunity for SAHM during their lives. On the positive, they have terrific relationship with grandparents who also have them involved in sports activities we would not have time for alone.
Therefore, there is no perfect choice, but if you want to live very CLOSE to parents, there is no substitute.
AND- we had another friend whose retired parents chose to rent an apartment close to their grandkids, to spend 6 months of the year near to them, so it can work both ways!