Disagree. I started with the exact Canon 18-55 II he linked to as an example of a kit lens. I've since upgraded to a lot of different lenses including some primes and the 17-55 f2.8 and while the 17-55 certainly gives me better photos than the 18-55 did (which is why I spent the ~$1000 on it), the photos I took with the 18-55 were clearly superior in image quality to any cellphone or P&S camera photos I've seen to date.
IME the photos on that review page he posted for that kit lens are not actually indicative of the quality of that lens.
If you take his argument a few steps further, you shouldn't buy a DSLR with a crop sensor, because you aren't getting the highest quality, and then you shouldn't buy a DSLR that is full frame because medium format is better, and so on... Quality (vs price vs convenience) is a range and crop-sensor DSLRs with modern kit lenses do have a very solid spot on that range.
In any case, most people probably shouldn't buy DSLRs but not because they will only use the kit lens but because DSLRs aren't pocketable and most people just aren't going to lug around a non-pocketable camera, even if they think they are (this applies even to the newer small mirrorless interchangeable lens cameras which are certainly smaller than DSLRs but still a bit too big to be pocketable in most situations).
I own a video production company where we exclusive use DSLRs, and the 18-55 is a great beginner's lens. Here's the issue with prime lenses, like the 40mm pancake: beginners have little concept of composition and framing. A prime forces you to move your body into position to get a shot. A zoom allow you to fiddle and tweak without moving. When you are getting started, you need to be taking lots of shots. When you improve, you automatically know where to put your feet to get a good shot, and using fast primes is just a ton of fun.
Here's a recent fashion video I shot with the most inexpensive gear I have in my kit, namely a Canon T2i ($350 on Craigs), a 50mm/f1.8 lens ($80 on Craigs) and a cheap $20 monopod: https://vimeo.com/59777345 . Good results come from experience and practice, not expensive gear.
Don't forget about the hours of color correction and post production you've done on the piece. I agree with most of your points, but that's not what T2i footage looks like off the card.
Read his title he said "if you'll ONLY use the kit lense". ONLY. You said: "I've since upgraded to a lot of different lenses".
He's not talking about you. He's talking about the quality of kit lenses and why it really isn't worth the investment in a DSLR if you're not going to partner that with an investment in some good glass. I completely agree.
Edit: I'll add one more thing. For everyone saying that the DSLR they bought and use with a kit lens is better than any point and shoot they've owned, I would question if you are comparing two similarly priced cameras. Most of the time people upgrade to a DSLR and spend more than they spent on the point and shoot its replacing.
IME the photos on that review page he posted for that kit lens are not actually indicative of the quality of that lens.
If you take his argument a few steps further, you shouldn't buy a DSLR with a crop sensor, because you aren't getting the highest quality, and then you shouldn't buy a DSLR that is full frame because medium format is better, and so on... Quality (vs price vs convenience) is a range and crop-sensor DSLRs with modern kit lenses do have a very solid spot on that range.
In any case, most people probably shouldn't buy DSLRs but not because they will only use the kit lens but because DSLRs aren't pocketable and most people just aren't going to lug around a non-pocketable camera, even if they think they are (this applies even to the newer small mirrorless interchangeable lens cameras which are certainly smaller than DSLRs but still a bit too big to be pocketable in most situations).