E.G.

I don't see why the following very simple idea isn't good.

The People's Bribe
(1) Key decision-makers (KDMs) in the federal government are guaranteed a large income for life.
(2) Apart from whatever they buy with the above-mentioned guaranteed income, KDMs are strictly prohibited from ever accepting any salary, payments, gifts, or any other things of value. This prohibition is for life, is legally enforced, and if KDMs are caught violating it, they are severely punished (e.g., long prison sentences) and publicly humiliated.

It seems to me that three things can be said for this idea. It would work; it would be a bargain; and it's feasible.

It would work: The People's Bribe would eliminate major sources of corruption (broadly understood here as any sort of government decision-making that is distortively influenced by the prospect or promise of personal financial gain). In the status quo, corruption happens because non-public entities have financial carrots and sticks that they can use to influence KDMs. For example, a US lawmaker who supports (or declines to oppose, etc.) legislation that benefits a particular industry might be rewarded with well-paid consultancy gigs in that industry after she leaves office. In a People's Bribe system, a narrowly rational KDM would not touch such rewards with a ten-foot pole, because the upsides would be relatively insignificant from her perspective (she's already guaranteed lifelong wealth) in comparison with the downsides (risk of severe penalty if caught, public humiliation, etc.). 

It would be a bargain: Let's say that we identify 5000 people in the federal government as KDMs. This group might include all members of the Senate and House (535), all federal judges (1770), and some assemblage of others (say, the president, vice president, cabinet members, heads of executive departments,…). Let's say the guaranteed lifetime salary of a KDM is set at $500,000. Then the People's Bribe would cost $2.5 billion in salary in its first year of existence. As KDMs leave office and are replaced, the cost would grow (since we'd need to pay salaries to all past and present KDMs). There would be further costs too (enforcement, accounting, etc.). All told, the total cost might be tens or hundreds of billions per year. But my guess is that this would end up being small in comparison to the total cost of corruption, which I'd assume should be reckoned in the trillions. Also note that some of the cost is already being paid (these people are already receiving salaries and retirement packages in the status quo, e.g., members of the House earn a bit less than $200k presently). If the People's Bribe would indeed eliminate or significantly decrease corruption in federal government, it would be a bargain.

It's feasible: I'll mention three factors here.

First, in order for the People's Bribe to be feasible, KDMs themselves have to have an incentive to get on board. We would need Congress to pass laws to make this system a reality, and we would need a president to support it, etc. All of this seems very possible to me. I think the People's Bribe would generally be in KDMs' interests. Most KDMs want to be hugely wealthy (that's human) but they would be much happier, I think, if they could get wealthy in an entirely above-board and respected way, which the People's Bribe would enable them to do. I do not think KDMs particularly like having to scrounge for their wealth by bowing down before private interests in shady, borderline-illegal, and/or actually illegal ways. This system would spare them of such indignities while still allowing them to have luxurious lives. Plus, the People's Bribe would give them a guarantee of lifetime affluence; I don't think they always have this in the status quo. If I were a KDM I would see the People's Bribe as a huge boon.

Second, there would need to be public support of this idea. It seems to me that potential for such support exists. There is a common-sense explanation, that regular people can understand, of why this system would prevent corruption. The rationale for it is somewhat cynical, which I see as a selling point, because I think most people are cynical about these sorts of things. And people believe that corruption is a problem and would like to do something about it. Here is something that can be done.

Third, there will be many powerful people who have an incentive to preserve the status quo, and in order for the People's Bribe to work, those powerful people have to be unable to prevent it. I grant that people who benefit from corruption would try to prevent anything that promises to reduce corruption. But many powerful people, including many people in business, would also stand to benefit from the People's Bribe (e.g., if your competitors manipulate the corrupt system better than you do, you might like to see corruption reduced). I think the various powerful factions might end up approximately canceling each other out.

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I'm not claiming that the People's Bribe would solve all problems. KDMs would still make many bad decisions. Not all harmful behavior is motivated by hope of personal financial gain. Some harmful behavior is motivated by sincere belief, for example. And some of the most harmful behavior in US politics seems to be purely recreational (I think much of what is happening today is like this).

Some of the harmful behavior that is either purely recreational or motivated by sincere belief might be harder to pull off without a rampantly corrupt (hence manipulable) government, so might be curtailed by the People's Bribe. But I grant that the People's Bribe doesn't directly address those forms of harmful behavior. 

And there is a problem of identity corruption, as it might be called, that the People's Bribe does not address. Identity corruption occurs when someone controls KDM behavior by controlling who gets to become a KDM. For example, if you want your industry deregulated, you may be able to accomplish your goal by seeing to it that ideologically libertarian-minded opponents of regulation are the ones who end up in Congress. Then you do not have to influence them while they're in office, as they're already sold on a way of thinking that disposes them favorably to your interests. It's well known that this sort of identity corruption happens. Whether it would increase or decrease in a People's Bribe world is something I shouldn't guess about.

The general point here is that removing personal financial incentives from KDMs' decision-making processes will not by itself ensure good government. But I don't see why it wouldn't eliminate one of the important causes of bad government.