We were lucky--Brady was basically the most durable player ever--but it's worth noting that (1) the Pats had really good lines that they consistently dedicated lots of resources to (2) Brady basically didn't scramble -- not that he could have scrambled well, but it's not like he was going to scramble enough to potentially get hurt doing that (3) they always ran the ball a bunch, (4) when passing they tended to get the ball out fast thus minimizing hits (5) the Pats seemed to generally ok with taking the check down, throwing the ball at the RB's feet, etc when the play wasn't presenting itself. [On the flip side they do seem to want the QB to stand in there sometimes, often with minimal protection, when they're going downfield against a look they like.]It's not that he was never at risk but they put a lot of effort into minimizing the risk to the QB.
And of course Jimmy G got injured within like two games and Mac missed time in his second year so even with a system that protects the QB some you need a lot of luck.
Three statues, Kirk Cousins, Matt Ryan and Tom Brady, basically haven't been injured in over a decade. Meanwhile, Jameis and Stafford have broken backs, Lamar sat out the last half of the season, Jalen Hurts and Patrick Mahomes, super bowl QBs, are both nursing injuries that limit them. Lance lost an ankle, Jimmy G a foot, and now Brock an elbow. Tua, concussed. Josh Johnson, concussed. Justin Fields was hurt every week in the 2nd half of the season. Zach Wilson always hurt when he's not terrible. Mike White, ribs. I could go on, obviously.
It is kind of random, of course, but some people know how to avoid getting really crushed. And, obviously, Brady never ran and hasn't held onto the ball too long in a very long time.