Dead Space as a series is a rounding error at EA. Dead Space 3 vastly underperformed, so the series was canned. Simple as that.
>https://www.escapistmagazine.com/EA-Aims-to-Broaden-Dead-Space-Audience/
>“In general we’re thinking about how we make this a more broadly appealing franchise, because ultimately you need to get to audience sizes of around five million to really continue to invest in an IP like Dead Space,”
>Dead Space 3 had a strong debut in the US, becoming the top-selling game in February 2013 with 605,000 copies sold in North America

Compare that to Resident Evil, which routinely sells in the millions for mainline games.