WotC is not catering to a specific personality. They are taking the sum total of experiences they’ve had with the brand, i.e. past products, design decisions, sales, and feedback, and creating a game that will appeal to the broadest number of people. What they’ve determined is that the game that grognards want is not in line with the game that will meet their goals.
But luckily, this “general atmosphere” you describe is illusory, because a large number of games in the OSR community have been built with grognards in mind. It’s a talented community, well supported with products and adventures, and seems to be growing steadily. Hardly an atmosphere where people are considered backwards. No conspiracy, no nefarious plots to be had. It’s simply that one company is no longer aligned with a subset of gamers, but a ready replacement is there for that same subset.
But of course, this argument is not about having an entire community and multiple systems that support grognards - it’s about this one, single company not devoting their brand to appeasing them.