I'm going to give a very cynical response to this, but I believe all of these factors are relevant. I'm also going to be going against the grain of the political leaning of this forum. I hope that we can discuss the points where we agree and avoid getting stuck at the first point of disagreement.

Factors:

1. Typically, people who wish to be in power are not the people who really want to use power for some greater good. Police make great examples because their abuses of power are often made visible, but this issue goes all the way up to the top. To give an example from right this moment, that I'm sure withstands bipartisan scrutiny, just look at how much political posturing and hot air has stalled the Covid-19 stimulus that is currently being negotiated. [1]The last proposal from the dems included identity politics and various climate provisions. Whether you agree with the policies or not doesn't really matter in this case, what sense does it make to fight for these policies right now in this bill?

2. Our political system centralizes all decision-making power into two parties. Each party has massive influence and control, even to the point of 'rigging' their own internal election processes. As such, the average American has substantially less ability to influencer outcomes at the upper tiers of government as they often think they do. This is the reason there was such distrust of parties by the founding fathers. The solution to this is to either have unlimited parties (requires a different voting system, of which there are several viable options) or to have no parties at all. Then there is a need to institute concepts like a public veto/vote for when things go haywire (think Brexit, but ideally without the intentional political incompetence).

3. Removing those in power is a scary affair. If your government decides to do heinous (or criminally stupid) things and there's no 'political will' at the top to change course, the people must intervene. How much peaceful recourse is there? There are finite 'legal' moves to be made, and they all take time. Once you run out of those options or time, the only remaining choices are 'illegal' and thus risky to individuals - and therefore require large groups of people to organize.

This is a problem understood by our founders, evident in their writings. It's also been commonly addressed since the 1800s in sayings like: [2]"There are four boxes to be used in the defense of liberty: soap, ballot, jury, and ammo. Please use in that order."

4. Both parties in the United States, despite their protestations to the contrary, have proven to have corruption up to their highest levels. [3]Both Democrats and Republicans dumped stock running up to the current crisis - after they were briefed about the risks. There's also intense 'fighting' over entirely manufactured issues. [4]One example I use often is "assault weapons," which are used to commit murder less than half as often as people's fists. It's hard to even imagine how much progress could be made if the same political energy were expended on more impactful social issues. (Targeting poverty which leads to desperation and organized crime might be a good start).

[1]https://www.wsj.com/articles/the-pelosi-schumer-contagion-11...

[2]https://en.wikipedia.org/wiki/Four_boxes_of_liberty

[3]https://www.politico.com/news/2020/03/21/coronavirus-trading...

[4]https://ucr.fbi.gov/crime-in-the-u.s/2017/crime-in-the-u.s.-...