I actually think there’s optimum voluntary and non artificial turnover where people naturally move to other opportunities. And conversely a calcification where people get stuck in a comfort zone.

I don’t think people should be forced to leave. Instead I paradoxically think people should be hired more interested in growth and this more likely to leave / move around the company / try different roles.

The entire second paragraph is about finding optimum turnover to keep the team fresh and dynamic. I think it's impossible to control organic voluntary turnover, as you don't control people's lives/desires. The alternative would be artificial turnover, moving people in and out of teams as needed to meet this goal. I think people joining and leaving is disruptive regardless of it being organic or artificial.