Don't get the stepping stone logic at all. So what if they do see us as a stepping stone? They would have to get us in the top 6 and probably promoted to gain the interest of the types of jobs they presumably want to step to.
I think by that point the writing was on the wall and DK probably didn't want to hand out a contract he might have to terminate within a fortnight.
I suspect he was going to be sacked if we lost v Luton. It's somewhat unpalatable to sack a manager after a win.
I think most foreign (european) leagues are generally a better place for developing the skills needed to be a head coach/manager than league one and two.