New World marketing department has tried to brand it as anything other than an MMORPG.
Marketing departments try to avoid MMORPG as a term to sell games to The Average Gamer.
It's ridiculous to assume you can trick people into playing a game by calling it something else.
If a video game requires an online connection, involves playing with lots of other people in a shared world and has a persistent landscape, it's going to be realized as an MMORPG.
Marketing teams try to set different expectations for the future of the game than what they are initially.
Sometimes words are used to define not what the game is but what it is expected to be.
Calling the game a one-time purchase ARPG will be enough to keep everybody satisfied.
People are trying to make the best of an awkward situation with some creative marketing when they have nothing but bad options.
When Amazon says New World is something other than an MMORPG, it doesn't really mean the game as it exists has changed.
It's simply signaling that it doesn't plan to support the game with MMORPG-tier content the way MMORPG fans expect.