I can understand not coming to XBox one as that's being discontinued shortly but a recent release said :GTA 6 is said to be unlikely to come to Xbox One or PS4.
"With the PlayStation 5 still hard to find at retail amid worldwide semiconductor shortages, Sony has canceled plans to discontinue the PS4, extending the system's life through 2022."
If EDO merely hinted or announced a PS5 release was just possible, I would get a PS5 in anticipation, but no announcement as we all no, so will stay with PS4.
and a recent release about GTA6 (Tomsguide) :
"As for the consoles you'll be able to play it on, the potential 2023/4 release (of GTA6) means we'll be firmly into the PS5/Xbox Series X generation. But it's possible that Rockstar will release a version for the PS4 and Xbox One if it's feeling generous."
Rockstar know where there customers are - more platforms covered = more filthy lucre, as opposed to the limited release of EDO on PC only.