I think both things can be true - performances (aside from Norwich and QPR) have improved but results haven’t.
Under Cifuentes we were lucky to get a lot of the points we have. Under Rowett, we’ve been unlucky to not accumulate more points (Stoke, Watford, Preston in particular).
I’d be willing to bet if we’d had Rowett from the start of the season we wouldn’t be in the relegation conversation, though we likely wouldn’t have been pushing up the top end of the table either.