SOXY, I just caught part of the interview on WGBH that Eagan and Braudy(sp?) had with the BOSTON GLOBE's Brian McGrory who said what I've been saying (more eloquently of course). The "establishment" in the Repub party has taken their voters for granted - promising one thing for their vote, and once in office ignoring them in favor of their big donors. A sufficient number of these voters are sick 'n tired of it, which probably explains why the likes of Trump gets their support - they know they're not getting anything from the current Repub "establishment" and they're willing to take a chance on Trump.
imo, for the "establishment" in both pol parties to ignore the frustration stirred up by Trump would be suicide, imo.
Also, it's interesting the two candidates who will likely win their party's nominations have high negative ratings.