And there was me thinking that there was 21 months between the two events.
If he had left after the cup final in 1989 I would have agreed, but waiting almost two years when there was no doubt that the team was in decline does point towards him throwing in the towel because he didn't have it in him to rebuild.
Try reading his book, the chapter on Hillsborough makes very clear the emotional price he paid after Hillsborough and that the heavy burden of leading the club through difficult times - so much so it lead to his ill-health and him taking it out on his own kids. And so what if took 21 months? Grief, PTSD, tragedies etc don't clear themselves up after 6 weeks.