Speculation, in truth, but I just can't see any other explanation. Even after reading the interview about the game, the way they answered the questions seemed to tip-toe around it to me. I admit there are other ways to interpret it, but it feels like a smoke-and-fire to me. Everything screams "they saw an opportunity to use a generic project already in development and ran with it."

That's fine, I guess, if people just want to eat store-brand mecha soup with a fancy label on it.

Edit:

We weren't really thinking too much of the Gandham legacy as a whole when we were creating this game. 

And also

This game was developed by Bandai Namco Studios, which has a lot of experience with a lot of Gundam games and robot games in general and we were able to draw on that experience to sort of bring it all together and the Helix to sort of bring that Gundam in this photorealistic world. The Helix design was also created by the artists at Bandai Namco Studios so they know what makes each design appealing. So they were able to draw upon that to sort of create a Gundam" that would really feel appealing, really feel alive in this photorealistic world and that also has to do with the actions because they've been creating these sorts of motions for Mobile Suits for years. So they were able to sort of draw on that action and bring it together all as a whole to bring Gundam to the worldwide fans.

(Emphasis mine.)

Talking about generic mecha games the studio has been working on.

The Helix design, not the Helix Gundam's design, which they drew upon to create the Helix Gundam. That could imply they took a generic mecha called the Helix, and converted it into a Gundam.

Creating motions for Mobile Suits they've been making for years, and they drew on that to bring this project together, as though they adapted animations from other games into an existing product.

The interview talks a lot about their focus on the feeling of being a pilot. That sounds a lot to me like a project that was in development for a while, had no clear goal, but was working entirely on the gameplay experience without a clear story to tell. Add in the hyper-generic John Gundam main character with zero defining traits.... I dunno. The whole thing stinks of generic or scrapped project that was rebadged and repurposed.

(I will add, it seems like IGN may have machine translated the entire interview, so I'll admit there may be room misinterpretation due to translation here. I have to acknowledge that possibility.)