??? Did blu Ray expensives , Did DVD expensives . Not all the things made by Sony are expensive . Also why would they one to fuck their product . Also their newest statement said they want all PS4 player to move to PS5 as fast as possible, which is lead an affordable console's on mind.
They are not stupid, unless you have a weird opinion with Sony or Playstation as brand.
Blu-Ray was a mass-market product and Sony wasn't the only one who produced those, it wasn't proprietary. In this case however, it would be proprietary, which in general means it will cost premium money just for the "privilege" to own them.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/