Not that I condone the practice, but the populace has learned to recognize that rabbonim and poskim have their areas of expertise. Certain ones are keen on kashrus, others on Choshen Mishpat, others on Shabbos, etc. In fact, I have asked shailos of many rabbonim, and have often been directed elsewhere because of the issue of expertise. The result, I fear, is that the average frum Yid can now pick and choose whom to ask, and does so. With this becoming a pattern, there are those rabbonim who are known for being particularly lenient or strict on specific subjects, and the choice of whom to ask is predicated on the expected psak. For that matter, batei din fare similarly, with those specializing in gittin, Choshen Mishpat, and with reputations of being fair to women more than men or vice versa.
The OP implies that there should be a return to the words of Chazal עשה לך רב. My agreement or endorsement is unnecessary. But I do wonder how things got this bad.