Do you remember why Nixon resigned? It had nothing to do with the break-in at the Watergate hotel. Had Nixon simply turned over the conspirators, none of this would have happened.
When Trump faced the same type of issue with Flynn, he fired him. Notice Flynn is no longer a story. I suspect that Trump and his advisors are completely aware that the coverup is worse than the crime. Going forward, even if, and that’s a pretty big if, they find some sort of collusion. Trump need only fire or distance himself from the conspirators.
Also, Obama was well aware of the “Russian meddling” more than a year before the election. However he didn’t do anything about it because he didn’t want to taint the election of Hillary Clinton. I’ll ask a simple question. If Hillary had won, would you be just as enthusiastic about the “investigation”?