I've been at the same company, and in the same team/dept for all that time. When I started I was in my early 40s with a family and had moved three times in the previous four years, and I was certainly ready to stay put if I liked the job. It turned out that the job was great. We were a small and scrappy team, fighting for recognition in a big company, and we got the recognition and grew explosively. The comp and benefits were good, and the management humane. The growth meant I had opportunities to do new things. I became a tech lead and then a manager. As a manager, I got to see how comp, and promotion, and hiring, and firing worked. And I got a lot more empathy in general for the work that management does that ICs generally never see.
After a few years I got tired and somewhat bored with being a manager, and asked my director to move back to a senior IC role and he facilitated that for me.
TBH, I have always had my doubts about the narrative that short tenures are the norm in tech. It has always sounded to me like a misreading of the statistical distribution: if you were to histogram the length of tenure of every job (person+company) in tech over some period, of course there would be a big hump at the left end. That's natural, because they are short. I myself have three jobs of less than two years and one each of six, eight, and 15 (if you count grad school as a job). So that's 12 years in the the four shorter stints and 23 in the two longer ones.