each time there is rumours of connection with the next PS console like the PS4 was suppose to "be able to play on phones and etc" but ended up just being a regular playstation console with more power and a share button. Don't think there will be much more to it, although they kinda need to since you could just buy a ps4 pro instead and the PS5 needs to stand out from it.
Technically, the PS4 can be played on phones. And tablets. And PCs...........