We used to admire well-known successful people who were modest/humble. Insufferable conceit replaced it. Why is it lauded/applauded?

  Who is "we" and when did this supposed admiration take place?  Your statement is only partially true, because in addition to modesty and humility, people showing the opposite qualities also received their share of followers. For centuries, some people have heaped scads of flowing admiration upon some of the loudest, brashest, most flamboyant figures around, be they heads of state, políticos in general, entertainers, sports figures, scholars, artists, socialites, military personnel, the list goes on and on. The pretense that there are bygone "good old days" ignores the fact that even during those good old days, someone was yammering about how much times had changed for the worse since their perceived good old days.
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