Unless I started cheating and using a bunch of momentum, I don't think I could do another rep beyond this. Now to be totally clear, I'm not saying that's how you should train on every set. But if you're not going close to absolute muscular failure, you're not going to be lifting hard enough to stimulate maximum gains.
Now, you don't have to necessarily go all the way to muscular failure. You can go to failure if you want to, but just perform that set using whatever level of intensity you're aiming for based on your own approach. I have discovered that if I take pull ups all the way to failure, my central nervous system is shot for the next few days. So I keep one or two reps in reserve in this particular exercise.
You certainly don't have to train to failure every set, but you do need to train to failure here and there to get an understanding of exactly where that point is. Not to mention that for maximum muscular gains, I do think there's value in going to muscular failure and that, generally speaking, high intensity training used in moderation provides benefits you can't get from always leaving 1-2 reps in reserve.
Thanks for reading!