The game's focused on Aloy and her journey, also what this world is about, so no it doesn't need a multiplayer, nor would the game benefit from it.
There's nothing lazy about putting everything into making the gameplay for a Single Player, Story focused, massive open world title, with tonnes of detail and things to do.
It's been compared to The Witcher 3 in scope by those who have talked about it, that's a game focused on Geralt's journey.
Hell even something like Fallout where you create an avatar that represents you doesn't make much sense to have a multiplayer, because it's about you exploring that world.
When games like these take so long to make adding MP would just be tacking on elements that don't add to the core experience the developers are trying to make. It's their game to present to the world.
If you don't like it, then you don't to buy it or even look it up past seeing the first trailer if you happened to stumble across it on YouTube or something.
SP only games are fine, provided they have a good level of value in the amount of content the publisher asks you to pay.
