Well, it could also be because Biden's discovery (a) was smaller and self-reported, (b) his legal team helped in resolving the situation, AND (c) the documents have been recovered in both cases and the ball is now in competent authority's court.

It's like this - say you and I both run over someone. I hide the evidence and try my best to prevent my guilt from surfacing. You, on the other hand, co-operate with the authorities and accept your blame. Which story is more likely to linger longer in the papers? I'd say mine simply because I'm being obstinate and refusing to do the right thing as expected by the law and by common decency.

I'd say that's why Biden's story died because of this.

Let me restate your example of running over someone:

Let's say you and I both run over someone. I did it last year, and you did it 6 years ago. You say nothing for 6 years, I say nothing for 1 year. I get caught, and provide no cooperation whatsoever. You watch me get caught and excoriated in the press and decide you need to fess up and cooperate. 6 years after the fact.

That's a truer representation of what actually happened.

The Biden team discovered some very old files nobody ever knew were missing and turned them over immediately.

Trump meanwhile, clearly intended to take these documents, clearly lied to the feds about having these documents, gave some of them back when the feds said they knew he had them, lied about having more, and other stonewalling tactics. The feds TRIED to keep this hush hush for like a full year. If Trump would have given everything back at the first question, we might never have even heard of it.

IIRC the first instance wasn't, it was the second and third that were afterwards.

Also the FBI knew about and helped secure the documents Trump had before they were "discovered".

Don’t think it’s malicious.

Trump is the war-machine establishment, bro. Recall he wanted (and according to some stories yesterday, still wants) to invade Mexico.