As with any attorney, Barr is only familiar with laws he has been exposed to. There are very few attorneys on Earth that have experience with the Espionage Act, and exactly zero attorneys who are experienced with charges brought pursuant to it while bound by the Presidential records Act and Former Presidents Act, the latter being one I have yet to hear one single attorney with an opinion even reference. That is the act that allots a period of 30-months to transfer Presidential records, its not in the PRA.
Even NARA themselves misstate this since they operate exclusively under the PRA without any authority whatsoever, including the authority to make any rule on it.
Barr's opinion on Trump's behavior, clearly without reading the indictment, and it's not a relevant legal opinion anyway.
Regarding your last two comments, federal court is very different than jurisdictional court. The federal rules of procedure prohibit bringing any case without legal basis into court.
Unlike jurisdictional or state courts, federal court Judges appointed to the case have a judicial obligation prescribed in law and the rules of federal procedure, to ensure the legality of any case presented to the court prior to allowing it to move to trial.
They also have the power to dismiss a case completely on merit without any motion to do so.
Thus, if the case is without legal merit, Judge Cannon lacks the ability to allow the case to go to trial. Allowing a meritless case to go to trial is unlawful and that's why it takes so long for federal cases to get to trial.
She will have to write a legal judicial opinion stating why she allows it and that opinion will have to have a legal basis in law and/or case law. This is unlike jurisdictional court where it's allowed. This would happen if a motion to dismiss is denied.
To prove a count has basis in law it must show a violation of law evidenced to a point of reasonable probable cause, a violation of law must consider provisions and exemptions that apply. Smith did not do this on any count. The Presidential Records Act and the Former Presidents Act exempt Trump from every single count alleged. For the indictment to be perfected, each count must explain why the evidence that shows probable cause is not covered in the provisions or exemptions that overrule the applicability of the laws that prohibit the action.
It's as simple as opening the indictment and searching for the words "Presidential Records Act" and "Former Presidents Act" . If neither exist, the case is baseless.
The foregoing act are coded as 44 U.S.C. Chapter 22 and Public Law 85–745 (3 U.S.C. § 102 note), the don't have to use the titles of the act. Here's the spoiler, neither exist in the indictment.