That is a profound question.

There were many unknowns after 1-6 despite the obvious actions by the Trump forces. On top of the cool-down argument of the MAGA mob, there were many historical reasons to delay and nail down the details of how far the infection had spread. Two issues resembled the McCarthy era and the WWII spread of fascism within Congress. Strangely enough, we were also facing the ramifications of a president using the Roy Cohn handbook of the big lie, delay, countersuit, and deny strategies. Don't forget a young Donald Trump actually retained Roy Cohn.

Allowing insurrectionist politicians to roast in their own juices could allow a few of them to come forward and inform on others.
The gears of justice are designed to grind slowly.