Are they really though?
On the topic of boots, let's say we're talking about high-cut hiking boots. I'm not an avid hiker. I do casual hiking sometimes so I just wear regular shoes to those. When I do slightly more strenuous hiking, I wear a specific pair of high-cut hiking boots that I own. I get a chance to do this maybe once a year, or less.
I bought a pair of Denali ones from Big5 for $40 for this purpose. It has been with me for 10 years now with barely any wear. If I don't use it often enough, it makes almost no difference to me to get a $400 "more durable" pair. The $40 pair is not going to get worn out in another 20-30 years at least. I probably won't go through more than say 2 pairs of these in my lifetime.
Is that an uncommon example? Maybe, but I'm not sure it's as uncommon as one would think. How about a travel backpack? I used to travel multiple times a year. Now that I have a young kid, I don't anymore. I go with a $20 backpack that I've used for a number of years that is still in decent enough condition to keep using. I'm probably not going to get much use out of it for the next 10 years before my kid is old enough to travel around the world with me.
How about a cast iron pan? They aren't dishwasher safe, and as a parent, I save time whenever I can. I don't own a cast iron pan, but even if I do, 99% of the time I'll pick up one of these non-stick sauce pans I bought from Costco as a set for a decent price of good quality that is dishwasher safe, when cooking. I've only owned these for a year but based on my experience with past sauce pans, one usually last me a good ~10 years, and that's with very regular home cooking. The iron handle skillet on this site costs $180. The set I got from Costco costs about that much, for a set of 4 pots and 4 pans.
Overall, I'm not sure I buy this entire idea of "buy expensive durable things because it'll cost less in the long run". That just hasn't been my experience in most cases, other than some very specific examples.