First of all, Rauschenberg actually seemed interested in them. Lichtenstein , for instance, was also interested in some aspects of the popular media, but his attitude was benignly anthropological, mildly amused - in other words, intellectually respectable. Celebrity, when it came, was something to be suffered rather than courted. They forget that the boundaries are reformulated as quickly as they are broken down, and that this does not involve any progress. Though all this gained Rauschenberg a trendy rabble of followers, it did not endear him to the hardcore New York art community.
Power is in turn threatened.
Rauschenberg ran across all this with a suicidal blitheness. The politics of exclusion is the major weapon of an elite which constantly reassures itself by turning away from the gross values of the masses. Rauschenberg carried the day when fashion forced the art community to go along with him - until that moment in 1964 when he won the grand prize at the Venice Biennale. This popular success released the furies and marked the end of Rauschenberg's career as a dominant and untouchable figure. At the time this was adjudged a phenomenon, but it was simply the first of a series of retrospective exhibitions that, inexorably through the sixties, summarized potentially major careers and disposed of them.