Yep. Either you're going to have to switch carriers to get access to a more recent Windows Phone or switch platforms.
And since there's no sign of any meaningful development of W10M in the near future + no sign of any new phone, let alone one that's VZW compatible, I think the question becomes whether to jump to a different platform now or later.
Of course, there's nothing stopping you from grabbing a used Icon or anything. I have some old phones on old OSes that'll still work fine (Well, for the basics at least) if I wanted to use them.