It’s lack of direct evidence. Trump operates like a mafia boss. No paper trail, always use euphemisms for direct action, use intermediaries for voice communication. That’s why everyone around him got caught and prosecuted, but he didn’t. The entire case would be hearsay interpretations. Federal guidelines wouldn’t let a prosecutor take that to trial. Usually in that case they go for intimidation to get a confession, which doesn’t work on a megalomaniac narcissist.
It’s not a policy question it’s a media question. The right started taking over news media the day Nixon resigned. Repealing the Fairness doctrine, ending League of Women voters debates, propping up Fox news, and Sinclair media buying out all the local stations. That’s the decades long community goal they’ve been running. The left needs to understand it, and how to fight it, because MSNBC isn’t doing it.