Everyone's entitled to an opinion but personally I don't understand the "taken us as far as he can", "won't get us promoted" etc arguments.
Reasons why we're lucky to be in the Championship:
Fanbase - we have one of the smallest catchment areas in the entire football league. Blackburn is increasingly Muslim who aren't interested. Kids increasingly gloryhunt City, Liverpool and Utd on our doorstep.
Attendances - thanks to the above, plus it being a low wage area, we have among the lowest crowds in the league even selling below average priced tickets.
Income - not much TV money outside the PL, so our income is dictated by the above 2, i.e. its very low.
Squad strength - dictated by transfer and wage funds, so income. Take Brereton and Gallagher out, ours is cheap as chips.
Reasons we should be in the PL:
We were in it most of the 90s/00s - contributes 0 points per season.
We won it in 1995 - contributes 0 points per season.
We won the League Cup in 2002 - contributes 0 points per season.
Our expectation-levels should now align with the likes of Preston, but I've heard louder boos at Ewood for draws than Preston fans gave their players for getting beat 4-1 in a derby.
The fact that Mowbray has been getting stick this season given all the above is insane. I honestly think we've got the most entitled fans in the country, and as long as that continues, every Rovers manager will get undeserved stick based on delusional expectations.