I don't doubt your premise but only Blaze can really speak to it's truth and what he says in the press may differ wildly from the reality that only he knows.
But those musicians you mentioned had/have decades under their belt at a high level that many fans appreciate. I can't imagine any one of them being fucked for 3yrs of touring because of a slow start. If they were that susceptible to such things then they wouldn't have lasted so long, I don't think. A good start would have faultered eventually for lesser performers.
And sure Newstead had his bass turned down on Justice and was basically bullied from the get go and yet he still more than held his own live, motherfucker owned that stage at times. Because he was big enough for the job.
Having watched that Wolfbane video I think that the only world in which Blaze succeeds emphatically in Maiden is immediately after Di'Anno or in place of Di'Anno. Wolfsbane Blaze could easily front Early Days Maiden and be adored.
A top lever performer would not be ruined by the roll of the dice, they would transcend it. Maybe a good, quick start in the live arena would have allowed him to grow accordingly, it's entirely possible but I doubt it. If someone is of a level to front Iron Maiden then nothing will prevent them from showing it. Bruce fought nightly with the band leader on his first tour. On his first tour he went against the leader of the biggest band he'd ever been in, surely a man with a reputation already and yet he did his thing regardless of the circumstances and he thrived. That's elite level. And no shame on anyone not being at that level but the levels are clear for me to see all the same.
Or I could have just said "yip, agree to disagree" but where's the fun in that?