There is a contradictory correlation there. Politicians don't learn their lesson because they are never held accountable. "Move on for the betterment of the country" has been the excuse since the post- Civil War era. Politicians on both sides (intentionally or unintentionally) wreck havoc and commit crimes and the only price they pay is lifetime benefits and fat bank accounts. The only lessons that will be learned from the Trump era is how easy it will be to do again in a few years.
The problem is twofold. The corrupting influence of lobbying groups incentives politicians to do their bidding, which leads to those "fat bank accounts."
The second problem is that accountability is in the hands of other corrupted ghouls. That's why the Dems didn't go after Bush or Trump for war crimes. They couldn't resist looking for
anything to hang Trump on, but they didn't go after the major offenses. They couldn't without indicting themselves.
Now you have some key figures in the Democratic Party calling for a sober response towards Trump and a focus on issues like the economy. I can only speculate about their motive. Personally, I believe they finally realize that Trump hate is no longer enough to keep them in power. They have to actually put in the effort to govern while opposing Trump's
policies and appointees. They're walking a tight rope between pleasing their donors and pleasing the voters, which is why it'll be interesting to see what they actually do. I'm not expecting much, but the fact that they're at least
saying what the voters want to hear shows that they understand what the voters care about. How that translates to their actual governing style going forward remains to be seen.