Sony's stance over BC is pretty simple, they don't believe that people are going to use a next generation consoles. I think this is deeply troubling for PS5 and regards to PS4 BC on the console.
IMO if they are saying things like this about BC then it pretty shows their philosophy regarding BC for the next generation Consoles.
PS3 had a PS2 chip inside to ensure backwards compatibility, yet it was expensive to make and PS3 was a major money loss for years because of that. PS3 and PS4 can't do BC because of technical problems regarding Cell and X86-64.
It's possible that they may have technical problems getting BC onto the next gen PS5. The Ryzen and Jaguar architecture are significantly different and without abstraction for their software, their software will no longer be compatible due to the difference in the instruction set for the Ryzen Architecture and the PS4 software that ran on Jaguar. The PS4 had problems running PS4 games for a while and needed a boost mode and a specific patch to make it work.
We don't know about how the PS4 OS and it's applications are designed.
It's deeply concerning about Sony's stance on BC and the future of BC on PS5. If PS4 Pro had problems running PS4 games when running on essentially the same hardware but overclocked, imagine when everything is different inside the PS5.
I think it shows how long term Microsoft was when designing their Xbox OS, ALL their games are inside a VM, so it's more adaptive to architecture changes than what PS4 OS is.
It's from Sony and Microsoft is that we will expect only iterative upgrades to the current lineup, yet Sony doesn't believe in BC? Seems odd.