That's when I stopped jailbreaking, when they stopped releasing untethered jailbreaks. I think the last phone I JB'd was a 6s I think it was iOS9.
Back then there also weren't too many extra features introduced during the yearly iOS revisions, so once you had one version JB'd, you could stay on it until a next version came out, or until the next major iOS version. Its different now, and so many more devices are in the ecosystem that don't play or at all if you don't have a certain version.
Besides, iOS matured enough to have a lot of the features us early jailbreakers used to tweak stuff Apple just wouldn't do. I still wish I could tweak some things that bother me to this day.