I was thinking the same thing. IMO, he either refinanced his home and/or used an HELOC, so that he could borrow some money based on the value of his house, which is why the amount he owed wasn't decreasing as fast as it should have. It would be nice to have a better financial profile in this kind of articles...
I saw something the other week about the Canadian home situation. From what I remember, they don't handle home buying the same way as the U.S. does. They don't have 30 year fixed mortgages then you own your home once it's paid off. They have adjustable rate mortgages that change all the time and constantly get renewed, so your payment can change drastically and you can't ever pay it off.
I'm Canadian. You're right that our mortgages are basically all adjustable rate mortgages as the longest we typically can lock a rate in is 5 years. However, you absolutely can pay it off. Some people just choose not to and keep extending their mortgage. There has to be more to the story like I said. It just doesn't make sense.