There Must Always Be a Stark at Winterfell
So, of course this hasn't always been the case, since there's about 2 years (assuming each season is approximately a year) in between when Bran and Rickon leave and Sansa returns.
But it's an interesting premise, because, assuming that Winterfell doesn't fall in Season 8, will there be a Stark there in the years to come? Jon's descendants will all be Snows or Targaryens, and Sansa's and Arya's will be whatever name of whomever they eventually marry (assuming they marry). And who knows what's going on with Bran, either physically or emotionally. So who's left to carry on the name?
I'm wondering if this is a portent that Winterfell will actually fall...