Here are two positions most any politician can take, yet few ever do:
“If elected, every month I will impanel a new random jury of voters in my district. I will inform them in detail about my upcoming decisions, and will ask them for their choices. Then I will just do what they say. In this way I can assure you that won’t act on my own interests or those of my cronies or donors; I will act as would random informed citizens from my district.”
“I promise that, if elected, I will do X, Y, and Z. But I don’t just make promises; I show you I am committed to keeping my promises. My word isn’t my only bond; my house is also my bond. I have contracted with ABC law agency; they will give my house away to the first person that can prove that I have broken any of these promises.”
These ideas have been around for many years, and they would seem to give voters more of what they say they want from politicians: less corruption and more kept promises. Yet virtually no political candidates ever take these positions. I have to conclude that these positions would somehow interfere with voters getting other things they want from candidates. But what things? Some possibilities:
We elect politicians to raise our status by affiliation. Anyone can follow a jury, so that isn’t impressive, and our affiliation is weaker if we suggest we don’t trust them.
We prefer the hypocrisy of democracy where they tell us nice sounding things, making it look like we support them, but then actually do what we really want done.
Voters would reject a candidate whose campaign focused on such meta issues, and prefer to support a candidate who would better help them signal their particular positions on non-meta issues.
We elect elites we think are much better than us, and we don’t trust our own judgement relative to theirs.
By suggesting that voters might not trust you, you suggest you are especially untrustworthy.
Not all politicians only seek power. Even when given alternative options similar to cases 1 and 2, most voters still support power-seekers. Why?
Politicians don't do what you suggest because politics isn't about social change, it isn't about keeping promises, it isn't about doing the people's will. Politics is about the politician -- It is about obtaining *power*, then keeping the *appearance* that one is doing "something" for as long as necessary.
Your hypotheses about why politicians do not back up their promises with risk for them certainly sound very nice, but you neglected to mention the most obvious one, the one most congruent with the facts: politicians are hypocrites (many of them Social Dominant / psychopaths) -- they know they make grandiose promises and they have no intention of fulfilling them once they are elected.
Sometimes the most obvious answer is the correct one. Sometimes a cigar is just a cigar.