The poor sales of the recent Batgirl miniseries was taken by the PTBs that Cass couldn't headline a comic and not that folk hated the acts of hackery being performed on the character, despite many and vocal comments to that effect.
The continued ineptitude and hackery being inflicted on Dinah in GA/BC is enough to make readers swear off the title, and in so doing convince the PTBs that Dinah no longer has what it takes.