Don't underestimate the psychological effects underlying vendors' convergence on TSMC

It's like an extreme version of "nobody got fired for going with IBM"

Decision makers, even and sometimes especially in groups are not always rational. There are many cognitive biases that might make going against TSMC too difficult to justify

Also historically they have been the only option for __nm manufacturing, although transistor size is beginning to become irrelevant <10nm with different tricks having more of an impact on performance and efficiency