Also, IIUC, if you control all the causal inputs, then there is no regression to the mean. E.g. if there were a trait entirely controlled by genes + controllable environment (not the case usually), that trait would not have regression to the mean if you are selecting on / controlling everything. (And if the environmental part is totally tranmissive (which it generally isn’t), then phenotype selection also gets the causality, so there’s no regression.)
Also, IIUC, if you control all the causal inputs, then there is no regression to the mean. E.g. if there were a trait entirely controlled by genes + controllable environment (not the case usually), that trait would not have regression to the mean if you are selecting on / controlling everything. (And if the environmental part is totally tranmissive (which it generally isn’t), then phenotype selection also gets the causality, so there’s no regression.)