The death of The Amazing Eternals partway through its testing was a shock for numerous fans, all of whom were looking forward to the first post-Warframe title from Digital Extremes. But there were good reasons for stopping the title there, and according to publishing VP Meridith Braun, one of the big reasons was LawBreakers:
The competitive landscape at that time was pretty hefty. We just saw LawBreakers not do so great, and it was a fantastic game, so that was sad. That happened right when we were starting our closed beta for [The] Amazing Eternals.
Braun also noted that the game was “the right game at the wrong time,” while also attributing the unexpected resources required to make Warframe’s Plains of Eidolon update as good as it could be. It was a perfect storm of forces arrayed against the title, in other words; the one saving grace for fans is that the company would still like to revisit it at some point (though considering the big updates approaching for Warframe, it shan’t be soon).