Last book I bought was Fizban's last October. But I will pick up Journeys Through Radiant Citadel on Wednesday and then the Spelljammer set when it comes out next month.
Are you talking about the physical books only or also online copies through dndbeyond? Because I've bought quite a few in dndbeyond, skipping most of the adventure books, but haven't bought a physical copy since the pandemic started.
I bought Fizban's late last year, but I got Strixhaven for my birthday in April. I find I'm buying less WotC official stuff and more third-party, to be honest - I've probably backed a dozen 5e kickstarters and bought another half dozen 3pp books in that time.
Main reason it content. I'm not a big fan of adventure books, and even WotCs setting books are mostly adventures these days.