That's the point. Why do we need PS4.5? A PS5 in 2018/2019 will do full BC just fine, without any half gen shit too, no one pissed.
What is the point of a PS5? Would you not rather have a 4.5 with the power of 5, plays all your games, same library and user base. Developers know they can lean on the existing user base and not having to take risks with games only selling to the first wave of adaptors. Also, you would not have to get the new console day1 since your old console can play the new games albeit at a lower res and maybe with less sparkles. You can still play online with your friends regardless of which model they have. Finally no one gets left behing because of not being able to afford the new generation day1.
I do not understand the negativity around this. No one is taking away your games. You can still play the new ones for many years (assuming it will work like phones and their games/apps).
First people whine about the current generation of consoles being to weak. Now when there is a posibillity to get more powerful revisions people whine about that instead!?
If there are plans for an upgraded version every 3 years and forward compatibility would reach only one upgrade cycle, it would be easy to hide non compatible games on PSN/XBL. The one thing I can see becoming difficult is telling parents at the brick and mortar store which revision their kids have and if their console can play the newest game or not.
Anyways, Im 35, have the money for upgraded consoles and I am more then willing to pay for it. I say bring it on!