There is an answer that could fit. We all know Trump is an egomaniac. It could be his ego won't allow him to accept he won on anything less than his own merits. It's possible his subordinates acted without his knowledge for this reason. I'm not saying this is what happened, but you asked for a possible answer. I'm sure offering up this supposition will get me attacked again, but Trump's psychology provides a possible answer.
I'm not going to attack you for it, it is actually a plausible explanation.
I would counter that, if Trump wanted to show he won on his own merits, he'd want the investigation to affirmatively prove those guys acted on their own. He would not want the cloud of suspicion to be out there that he won via these characters helping him out.
Personally, I don't see it. Trump's own comments about not having had any ties to Russia when he was trying to do a deal for Trump Tower in Moscow; Trump drafting the fake press release on the meeting; Trump saying dirt was coming; his son and son in law and campaign chief all attend the meeting. Way, way too much coincidence for Trump not to have been told.
Now, it could be that Trump knew but did not think anything was really wrong with that. He was a campaign newbie, after all. And I'd be somewhat forgiving if he fessed up to that at the time. Some short term pain for him, maybe a censure, but we wouldn't even be talking about it now.
But no, Trump had to try to derail the investigation, undermine it, and lie. When he does that, it makes me think there was more to it, a quid pro quo, or some sort of indebtedness at work.