That wait was an unique circumstance and not at all the usual time between seasons. Usually, the wait was only a few months at most between one season finishing airing and the next starting. In fact in later seasons, they would begin airing before the previous had even fully wrapped up
The wait between S6 and S7 was much longer because the original series wrapped up, and they began work on the movie. A few years later, in 2022, HBO dropped it and left it in limbo, so after a while they had to shift focus and begin working on the continuation series instead, likely starting from scratch, so it also took another few years to release