The way I understand it, the kernel work is heavily subdivided into subcommanders and such; only a few people show code to linus directly.

So I imagine its extremely unlikely that any early contributer could be turned off by a linus rant targeting them. They contributor loss would have to be based on the fact that the rants exist at all.

My suspicion is that very few qualified contributors are scared off by the existence of Linus's rants. Maybe if it targetted them, repeatedly, but otherwise its difficult to imagine this is a significant source of loss.