single-world QM - that is, FTL, discontinuous, nonlocal, CPT-asymmetric, acausal, nonlinear, nonunitary QM

This is a perfect illustration of Mitchell Porter's point. This is not, in fact, what single-world QM is. This is, more or less, what the Copenhagen interpretation is. Given the plethora of interpretations available, the dichotomy between that and MWI is a false one.