I don't think he's incapable of it, it's just that recent history shows that it's not what he does.
I do take into account that McGregor will have holes to exploit, but I fully expect him to be the aggressor which will lead to Floyd fighting the way he has for most of the last 10 years.
Straight right hands, counter right hands, and movement all around the ring. If he does knock him out, it will be via a counter right to the chin rather than a flurry of punches on the offensive.