When Mike Bloomberg held a rally this month at the National Constitution Center in Philadelphia, the signs of his wealth and influence were everywhere. Former Philadelphia Mayor Michael Nutter, long a paid adviser to one of Bloomberg’s charitable programs and now to his campaign, warmed up the crowd with chants of “Mike will get it done!” That followed a performance of the Nick Jonas song “Jealous” by an a capella group from the University of Pennsylvania, where Bloomberg has funded public health research.