Politicians campaign on their legislative agendas and high profile initiatives. I think they underestimate how difficult it is to execute their initiatives once they become responsible for governing. They don't realize that they are working with large and powerful bureaucracies. The departments swallow up the political appointees with urgent day-to-day work, which slows things down even further. It's easier for politicians in office to bypass the bureaucracy than to change it, but that's not sustainable given the issues of today.
Politicians and public servants need to break down the power of institutional interests built up over the last half century, in order to unleash innovations (that I think people in government are itching to initiate) that can improve government performance and restore public trust in government.