MaRo on recent Secret Lairs selling out: "Most of the time you think of as 'print to demand' actually wasn’t. And that resulted in us destroying a *lot* of product."
They switched to print-to-demand in 2024 (or said they did) so just kind of more of the same from them: https://magic.wizards.com/en/news/announcements/speeding-up-secret-lair-shipping