Growing up and still today we had "assigned" seats around my parent's dinner table:
Once we left the house, my parents still kept their seat and even when we come to visit, our seats are always there and welcoming us to remind them of dinner as a family. My parents have purchased a much larger table they use in the dining room which hosts all the adults during our big holiday dinners as all four of us kids are married except for one. My parents have eight grandchildren with a ninth to be born in just a couple months. Now the grandchildren sit around the kitchen table my siblings and I grew up sharing many family dinners together at, with a few added chairs.
At our kitchen table we have musical chairs at every meal. No seat is claimed, but we are all together for dinner and sometimes even breakfast and dinner. Where we sit depends on the children and where they want to sit and who they want to sit by. I'm ok with not having an assigned seat at our own table, just as long as we are all sitting together that is all that matters (even if meal time is chaotic and sometimes downright stressful).