Sorry, but somehow I doubt that sales being down is due to the physical media thing. I think it more likely its due to the whole financial uncertainty, thanks to the corrupt rapist I the WH, and price increases caused by the silicon supply and demand mess.
It is not like the PS5 without a drive has not been selling, so lots of people have long time ago decided they don't care for physical media and supposedly there is lots and lots of pre-orders for GTA. If physical media was such priority, then neither of those would be selling.