Base game was released 2014 and parts of it developed in 2007 so as old as PlayStation 4 and most code and zones is still the same while newer zones are done similar so why should everyone have to upgrade console to keep playing game with same old graphics?
PlayStation 4 runs games with much better graphics like Assassins Creed Odyssey, AC Valhalla or AC Mirage, the last beeing released 2 years ago 3 years after PS5.
If new games are still released for PS4 or only stopped getting released recently why is ZOS late and must stop old console updates for a game from 2014?(Which as you can’t play old update means immediate shutdown).
Especially with rumors of crossplay coming soon and playerbase in decay many players won’t buy PS5 to continue ESO and eso cant exclude more players.