Why do we call it TRS and MVP, instead of SRT and MVP or TRS and PVM?
Because whether you use $MVP$ or $PVM$ actually depends on how you perform the multiplication: $vMVP$ versus $PVMv$, note that you have:
$(PVMv)^T = v^TM^TV^TP^T=vM^TV^TP^T$, where the last identity does not hold in math, but holds in glsl since vectors can be reinterpreted as either row or column vectors for convenience.

The same holds for $TRS$ and $SRT$. In general CG code and applications have an issue with sticking to standard established conventions, so you get all kinds of funny conventions.