Let's be honest here, Battleborn came out at the worst possible moment. Had they launched a few months after Overwatch, maybe it does better, or maybe it totally flops and we never hear anything of it again.
The problem was it didn't, it launched basically alongside Overwatch and it did not do well by comparison.
Another big problem was that people kept comparing it to Overwatch. Other than the cartoon style and both of them being shooters, Battleborn wasn't anything like Overwatch. It was closer to moba shooters like Monday Night Combat. It's a shame it shut down. I quite liked it.