Couldn't agree more!

how much grappling experience have you had?

We do takedown defense (as well as other grabs, etc.) as a regular part of our training regimen, and even sometimes work on being on the ground just in case. Murphy's law and all that. My sifu emphasized both the fear factor in being on the ground, but also that the same training we do for when we're on our feet applies just as well on the ground. I will say we had a guy with years of BJJ from some serious schools come in who was unable to get most of us on the ground (those of us with enough training under our belts, at least). He also told us he had to go ice his knees afterwards since we don't use mats. But again, we emphasize that someone should get lit up long before they get to you, and even if they make contact they shouldn't get you off your feet. With enough training, it works.

Another story. I've been at my current school about 6 years. I had previously trained at a Wing Chun school back around 2000, and was there about a year. I stopped when I moved to college. About a year or two after that, I tried BJJ a little bit. Honestly, I was not impressed. I couldn't stop myself from being taken down, but because of the relaxation from my Wing Chun training, I was pretty much impervious to joint locks. And this was my ~1 year of Wing Chun against people with like 3 years+ of BJJ. I'd imagine the guys who'd been doing it longer would've been able to do more, don't get me wrong, but even then I don't know how well it really would've worked (and that's without me counterattacking at all to boot).

I've done aikido as well, but with any of the grappling/throw arts, they only work if the opponent gives you a lever. Levers come from tension. Most people don't learn how to relax in a fight (It's incredibly hard), so most people will give them. But, I did notice that none of those arts could really handle a punch very well. The guy I mentioned earlier even said they assume in their training that they're going to take some hits while they close to grappling range, which is insane. What if the guy has a knife, like you described? What if he hits like some of the guys I train with (Wing Chun punches are a whole different animal)? What if there's 3 of them?

So my experience with the grappling arts is that they're fine for competition, and fine against someone who doesn't know what they're doing. But real life scenarios are a whole different ballgame.