Eh, I don't think this article is really seeing it from both sides. Sony doesn't care, because the market hasn't shown that they care. This article is making it about shaping the views of the consumers, when that also works both ways. Obviously they benefit more by selling you new boxes and games. But if they had evidence that there was a huge market dedicated to legacy gaming, I wouldn't put it past them to cater to it. Since one of Sony's strengths is their ability to check off the proverbial boxes of their competitors. PS5 is backwards compatible so that whole idea of them only wanting to sell you new things is moot.
They are doing what is cost effective, while catering directly to what their base buys, otherwise they could just make PS5 a PS5 only platform. Again they are still selling you cheap PS4 games so I don't think this is some campaign they have against old games, nor is this some focused campaign to make you think otherwise. They are focusing on their strengths and what the market has very much dictated as being of importance. The preservation of legacy gaming is a novel idea (one that Microsoft invested in for an advantage and point of differentiation) and I don't doubt they'll invest in it, from now forward, because everything is already in place for them to do so without much extra investment. To put it blunty, they just don't think it's that valuable and the market has not shown them otherwise. Maybe they'll change their tone and make a huge investment in it at some point, but it's always gonna be a risk/reward kind of thing and they've made it very difficult on themselves with their previous hardware decisions.