Studio founder Shinji Mikame left a year ago, not too long after HI-FI came out. So that's a big personality gone.
This decision wouldn't have been made on what's already been developed, but what's currently being worked on. So any thing that was currently being worked on would have been the cause,
Ten years to make one well received game. After two failed high budget titles, an attempt at a franchise, Ghostwire and a mobile game supported for only five months.
The studio head Shinji Mikami left shortly after Hi-Fi rush. So I would guess any projects they had in the works weren't interesting enough to justify the costs.