The article says nothing of the sort. They didn't phase it out. The article was released before the game officially was. It does actually say this though:

The danger for any game is simply that people stop playing, so the team focused on retention and on listening to feedback from the community to make Splitgate a “forever game” that can go years, with “seasons,” new features and maps, and so on.

Splitgate became a 2-3 month game, not a forever game. The game only had 1,600 players on Steam when it officially released, there wasn't even a spike in players on that day. It had one spike on 8th August 2021 of 67,000. The developers fumbled with their "lightning in a bottle" as they say in that article.

They are making a new one because it failed to retain the interest of the audience and the $100M from investors has to be made back, are they just gonna keep making new Splitgate's and pray on hype to sell as many skins as they can in such short amounts of time?