It takes obvious effort to overcome received habits from one's local idiolect, as for example underclass people did in England, last century, deliberately adopt

It takes obvious effort to overcome received habits from one's local idiolect, as for example underclass people did in England, last century, deliberately adopting an (imperfectly reproduced version of) the overclass rhotic affectation in an attempt at economic advancement. You are getting really disingenuous, now. Who are you performing for?