Cardiff have punched above their weight with the players they have for the most part of this season.
It seems mainly that they have accepted giving away possession in exchange for quick fire attacks through width and nabbing goals.

However that works for so long.
When teams work out that you can shut Cardiff down by defending high and then Cardiff are left with the option of either passing through the midfield with players of limited passing ability or pumping Long balls up the attack - their threat is significantly nullified.

I believe that’s what you’re seeing now.
Whether Warnock anticipated this would happen or not is a different matter but I would imagine he is working on a Plan B to counter.
It’s not like he hasn’t seen it before.
As ugly and as unattractive as Cardiff play is, it’s a tried and tested formula for Warnock.

Cardiff will likely finish 7th - 10th which is probably a very good result given the resources he’s had to work with.