Sigh. Didn't I already say that it's no problem beating AI army when he's full of mercs? What you're trying to say? That after a year instead of 50k of cannons and 500k merc infantry they'll get 40k cannons and 550k merc infantry? What does it change? It's still just a giant army of mindless undead. Before or after attrition. Army didn't become more or less dangerous, as well as attrition did anything useful for you. Well, excatly the opposite, you have to stay as a full stack on that siege, because a giant swarm of merc zombies actually can overwhelm you if you split.
Before attrition, Ottomans can easily have > 100k cannons and bring them to bear in full combat width back row against you when the zombies pile up.
After attrition, Ottomans have less than half those cannons and the fights get a lot easier. So it still matters, mostly because the AI is just that bad.
But it's a far cry from the advantages conferred by managing attrition in, say, patch 1.5.