we, of the lower, unenlightened and unrepentant life forms, still enjoyed a good fight and found that fighting worked great in aikido. in our delusional mind, we are undefeated and have no equal; thus, we have no opponents, since we have defeated them all. kinda like the Musashi complex, i have no equal; thus no opponent, thus no need to fight.
Thanks for the giggle, Phi. Back in the days of rec.martial-arts, we used to boast that we were undefeated in all of Asia. And, in fact, I still have never lost a match in Asia.
To try to address the topic seriously, I think it all hinges on what you mean by "fighting", "work", and of course "aikido". Different (but still reasonable) definitions of those three terms would give us answers ranging from "Hell no" to "Hell yeah", with a whole lot of "Maybe" and "Sorta" in between, and that's before we even get into the insane humpty-dumptying in which this forum excels. I guess for me, the phrase "in aikido" is a bit of a sticking point -- I understand that OP used this construction to mimic the topic of the other thread, but what's "in aikido"? Somewhere where the laws of aikido prevail? The only place I can think where that always happens is in a dojo, in well-regulated practice where people are kept from going off the aikido reservation. As with anything else, if you start by dictating the terms, of course you control the argument and its outcome. If you define "aikido", then you get to say who is and isn't in the club; if you get to dictate your conditions as "in aikido", it's really no different than a sparring match in which punches to the head are not allowed. Anyone can hypothesize a reality in which certain things are fact...but it's a stretch to say that because you can imagine such a situation, that it applies to the big wide world.
Another disconnected thought on the subject: sometimes, when he's working with someone and their technique breaks down (as uke or nage), he'll say "Now we're just wrestling" or "Now we're just grappling". He doesn't say that to disparage wrestling or grappling -- he says it to point out that when you go there, you've changed the rules of the game and given up a tool that you know somewhat (aikido) in favor of one that you may not know at all. What he's not saying is that wrestling, or grappling, or fighting, can't work against someone using aikido. Size, speed, experience in fighting, willingness to take a hit, competence at whatever it is you're doing -- all of these are factors in your favor, and there is no magic "whatever it is", aikido or anything else, that provides some kind of a magic bulletproof vest such that someone doing whatever-it-is is invulnerable to someone who is "fighting".
The response to that, of course, is that if you can be overcome by someone who's fighting, you're not doing aikido. Like all proofs by definition, it is an invalid statement.