I'd say look at the different scenarios. Imo, there's ony a few (of course, we could all get lucky):
1. Both have no experience- somebody could accidentally get hurt.
2. one has alot and one has very little- Obviously the one with alot will win.
3. Both have some- again, somebody might accidently get hurt. Usually the one with the stronger will wins.
4. Both has alot. This is what we train for, where, up against a hardened criminal or a punk kid MMA monster on steriods, you'll need alot more than Aikido to help you. You have to be prepared to bite off extremities, scratch out eyes, poke out eyes, beat to unconsciousness, cheat in whatever way, etc., to win. Not to mention have great stamina and will to live. The key to survival is to NOT run out of gas, NOT get knocked out, NOT get on bottom of a guard, NOT get surrounded, etc. If you do, you're done. LIke that scene in Saving Private Ryan, in the upstairs with the American soldier from Brooklyn and the German, with the bayonette, there's nothing scarier than realizing that your opponent is stronger than you and is about to kill you and there's not a darn thing you can do about it.
Also, fwiw, I would NOT rely on BJJ to finish a fight. Most good fighters nowadays knows BJJ. Besides, at no time do you want to find yourself on the ground, especially on your back.
Btw, my supplement to Aikido is a CWP and 9 rds of .45cal hollowpoint. There's NO WAY I'm gonna go toe to toe with a kid half my age or a hardened institutionalized felon.
Sorry, but until Aikido becomes a complete MA, able to defeat all others, a supplement is needed. It's all well and good to speak about spiritual stuff, like Zen and defeating yourself, etc, but the hard reality is if you don't take out your opponent, he's gonna take you, right now. Before you can say,"Please, don't."