In reality though, you wouldn’t ‘launder’ money that wasn’t ‘dirty’.

As an activity it’s basically always indicative of a crime. (Wether you agree with the law or not)

And by its very purpose, it makes the ‘base’ crime harder to prosecute and trace.

I think you’ve flipped the causality.

So I don’t think it’s so much that prosecutors just think it’s easier way forward, and if they put their mind to it they could prosecute the base crime, but don’t want to. As much as the laundering activity itself has made it too hard to prosecute.