To be fair, most Doctors have had a (video) tenure of around 2-4 years, some of those cut short by health issues or changes in lives, either a change of showrunner, or in one case loss of a colleague (in the case of Jon Pertwee). The extreme ends of that curve would be Tom Baker (7 years), Paul McGann (1 movie, 1 special) and John Hurt (2 specials). Even Matt Smith has actually fallen directly in the middle of the average at 3 years, and Matt Smith went for 5, although we also have the outsized impact of their storylines to consider in how it feels like longer, and that the post-relaunch period has a very different story structure that can provide more storylines per series.
"You know how parents tell you everything's going to fine, but you know they're lying to make you feel better? Everything's going to be fine." - The Doctor