For me it was Mad Magazine. What happened to Nat Geo, which I had little relationship with, was that they got bought out by an evil company.

This also happened to New Scientist, which I had subscribed to for decades. When they switched ownership, I was unemployed and had let my subscription lapse, and now I have a job, I haven't restarted it.

I still subscribe to SF magazines. I've been a subscriber to Asimov's since issue 1; I have been an F&SF subscriber since the late 70s. F&SF went more "woke" and more multi-culti recently - I think it's absolutely great, you must change or die. Long may be these two publish.