Back in 2016, Andrew House, then CEO of SIE, said this:
"I saw some data that really influenced me,” he said. “It suggested that there’s a dip mid-console lifecycle where the players who want the very best graphical experience will start to migrate to PC, because that’s obviously where it’s to be had. We wanted to keep those people within our eco-system by giving them the very best and very highest [performance quality]. So the net result of those thoughts was PlayStation 4 Pro – and, by and large, a graphical approach to game improvement.”
This is who PS5 Pro is aimed at - though I don't know if they succeeded with this mid-gen refresh, given that PS4 Pro offered much, much better bang for the buck than PS5 Pro.