Mueller found that Trump and Co. colluded with the Russians. He just couldn't prove that they clearly knew it was wrong at the time. Flash forward to now where Trump's lawyer and the Senate admits that Trump did extort Ukraine and he was pressuring them to dig up dirt on his political rival, but that it's just not a crime. He's been guilty on all fronts. Not innocent, not exhonorated: guilty.
So no, we haven't been wrong about him. He's just been slimy enough to slither away from having to pay for his crimes. But trust me, one day he will do something that not even the most kompromised Senator will not be able to help him get him away with. I just hope he hasn't completely ruined the country by then.