That's probably true and things were very bad at the time that he left, but I can't imagine they would have been any worse than they've been under Eustace.
We've won 3 league matches since JDT left. Would we have beaten Leeds? Probably not, but we would have picked up a win or two against the likes of Sheffield Wednesday, Plymouth, Birmingham, or any of the host of other bad to mediocre sides we played.
Would our goal difference be worse now? Probably, but we've also lost by 5 to Bristol City, by 2 to Sheffield Wednesday, and drawn against a weakened Coventry side that played a third of the match with 10 men.
So, are some rewriting history as to how bad or good JDT was? Probably. But the sad reality is that things couldn't have gone much worse since February.
He had to go, but let's not pretend that if we stay up it is because of some Eustace turnaround. I think JDT would have picked up a similar number of points. Fewer draws, more big defeats, but a couple of those draws would have turned into wins.