Usually a heating element dies or similar. If it were easier to replace the heating elements I'd think it'd help reduce waste, but as you and others have noted, that wasn't the point of the article.
The first was a two-slice Kenmore (RIP Sears) which still works. It cost $20 and was purchased close to 25 years ago. I only used this a couple times a week and now the usage is very sporadic, but it always works when I need it to.
The second was a Cuisinart toaster oven, which is not exactly a toaster but has ended up being our primary toaster. I have no idea how old it is since we bought it at a garage sale for $5 about 5 years ago. This is used almost daily, sometimes multiple times a day, and for a lot more than just toast.
I can see buying one more toaster, meaning a toaster oven, in my life, but it will probably be to get new functionality (e.g., air fryer, larger capacity, etc) instead of replacing something broken.
But I see your point, we've had multiple other toasters, some toasted themselves to death by melting their own plastic casing.
The saddest failure was a Krupp coffee maker, that thing was amazing, made the best coffee. Sadly I melted the power cord on a stove top. This was before I had a proper set of tools, so I gave up trying to remove the "security" screws, that would have let me open it and replace the cord.