Sorry to hear that. My dad has subscribed to this magazine since the early 70s (he's a college teacher in maths, geography etc.), and I remember looking through them periodically throughout my childhood. Part of the thrill was gazing at the gorgeous photographs. Sorry to hear it's become so watered-out by ads.
As far as I know the decline has been decades in the making. In 1998 or so I received a gift subscription--you know, because I fooled someone into thinking I was "learned"--and while the issues I got weren't exactly akin to Vanity Fair, the quality and interest of the articles had suffered a severe drop off from the great publication I remember as a kid. In fact, I still have their December 1985 Ballard finds the Titanic issue, an issue in which every article is simply outstanding.
Even back in its heyday, National Geographic had to tow an anti-communist line just as a means of protecting itself from the nationwide protection racket that all the right-wing agitprop created.
Now the ethos and tone will be "Murdochian", which has evolved from doctrinaire anti-communism combined with purile muckraking.
It'll be entertaining, no doubt, to see if the Murdoch acquisition of a prestigious science/photography/travelogue magazine forces the direct incorporation of the illiberal, illogical, anti-science, commercial dominance tropes that Murdochian media are famous for.