Are you sure? Can you guarantee that if these adventures and settings that are being published in modern 5e were actually published in the TSR-era of D&D, the version of you that played the game 30-40 years ago wouldn't have liked them? Are you certain that if one of the classic TSR adventures or settings that you liked 30-40 years ago were actually just published now for the first time, you right now would be as big of a fan of them as you have been for decades?I know I wouldn't be very excited about them. Worldbuilding matters to me, and those products don't care about it.
And . . . plenty of modern D&D products care about "worldbuilding". Explorer's Guide to Wildemount and Eberron: Rising from the Last War do amazing worldbuilding and get across the ideas, creatures, and locations expertly. Sure, Strixhaven didn't really care much about worldbuilding (which is a shame, because the small bits that we got with the Archaics and Oriq were really interesting), but that's primarily because the book is more of an adventure than a setting guide. I think that was a bad design decision, though. Ravenloft had worldbuilding. It added new bits of awesome lore that previous versions of Ravenloft never had (the Priest of Osybus's lore is awesome), including many of the domains of dread. I mean . . . the fact that they changed things is proof that they "worldbuilt," because the act of changing something in the setting requires that you replace it with some other bit of lore. Netherdeep worldbuilt, expanding upon the lore previously established for Exandria in its different setting books and the show. Fizban's worldbuilt, adding the story of the First World and giving an explanation for why Dragons are important in this game. Descent into Avernus worldbuilt, exploring the first layer of the Nine Hells more in-depth than ever seen before in the history of the game. They worldbuilt for Witchlight, adding more to the Feywild than we had before (Domains of Delight to reflect the Shadowfell's Domains of Dread). They're also making two completely new settings that have never appeared in D&D or M:tG before . . . so they clearly care enough about worldbuilding to have at least started the process of making two completely new worlds (the first ever in 5e).
So, worldbuilding absolutely happens in modern D&D. The fact that it happens (and happens really well in most products) proves that they care about it. Whether or not you like the worlds/settings they build doesn't change the fact that they clearly do care about it.