Over the years I've seen numerous thinkpad tweaks for wifi, sleeping with the lid closed, restarting wifi on lid open, numerous tweaks for the function keys (audio up/down/mute, brightness up/down), clock speed/thermal management, reading battery levels, etc.

Seems like the #1 reason thinkpads are well supported is that they are relatively popular among the people who modify the OS and kernel for compatibility.

I don't recall that Lenovo is a particularly big contributor to the linux kernel.