Why? Advertising need only work. That is, drive sales, change attitudes, or perception. For some audiences and brands that will be achieved with informative ads, but not all. Indeed, as an industry, we learned this a long long time ago. Perfume ads are a great example.
I agree with you on lots and lots of points, but a simple return to “salesmanship in print” in advertising won’t solve everything. (Or indeed, anything, necessarily)