Jean de Rochefort wrote:
One other thing I know...Aikido will keep you off the ground if you know what you're doing.
What if you slip on an uneven or wet surface. What if you're sucker punched and don't know you're in a fight until you're on the ground. What if there's several of them? There's a heap of situations which can have you end up on the ground before even getting to the "what if your technique doesn't work as well as you think it does" part of the discussion.
You've said previously that Aikido has an answer to every situation. "don't be on the ground" isn't an answer to the ground question any more than "don't fight multiples" is an answer to multiple attackers.