McGhee's predecessors did try and address the issue, however unsuccessfully. Baraclough signed a left back, McCall persevered with Angol when Hammell was unavailable. McCall brought through Carswell and Baraclough signed Grimshaw.
To say that these managers have ignored the problem is wrong. The problem is that the guys they've earmarked for replacing Hammell and Lasley haven't been up to the job.
What this tells us? Despite their flaws being pointed out on here, Hammell and Lasley aren't that easy to replace...