A data point: ~20 years ago I was part of a small team (<10 devs) developing a plugin in C++ with 5m installations. That company is very good at keeping their developers, some of their current devs started there >25 years ago. In such an environment, code ownership doesn't have a negative impact, so it has always been very strong there. Hence you can easily point at some part of their software and call it "this guy's part".
(I still have ties to that team, so I know this still to be true.)