The House committee had already received hundreds of pages of documents within hours of the ruling.
“The ruling denying Trump’s request to take up the case effectively deferred to a decision last month against him by the D.C. Circuit Court of Appeals, which had concluded that Trump’s claims for executive privilege over the documents ‘would have failed even if he were the incumbent’ president, the Supreme Court noted.”
Trump’s claim was meaningless, anyway. Executive privilege only involves the President’s ability to shield certain matters from Congress or, in some cases, the judiciary and general public. So if the Supreme Court had sided with him, he could conceivably have kept the documents from Congress. But here’s the rub. He could not shield the documents from the executive branch. That’s not a thing. If the courts had ruled that Trump could shield documents from Congress, Biden could have ordered his subordinates to place everything online immediately (probably with some redactions), in which case the House committee would have had access to all of it anyway. Trump undoubtedly realized all of that, and that everything would eventually come out, but I assume his strategy was to stall for time on any evidence not in his control, while destroying any evidence in his control before it can be subpoenaed. (That’s almost always his strategy, and has been since long before he became a politician.)