I think it has a lot to do with licensing. Companies feel safer using BSDs because there’s no fear of being sued under the MIT license, I suspect this is the reason sony chose FreeBSD for the playstations. A second reason would be quality vs linux, netflix has been line rate encrypted traffic with FreeBSD just because the network stack is (was?) more mature than linux. We used it at $job for zfs file servers because it’s native and much more mature than linux alternatives.