Ultimately, you've lived long enough at this point to know your shoe wearing habits to some degree. If you're the type to wear a particular sneaker day in and day out and are disappointed with the way it falls apart, it might be worthwhile to invest in a better shoe. If you wear a pair of leather shoes once a year, it might make more sense not to splurge, but if you wear a cheap pair often they're going to wrinkle and dull very quickly.
Do what makes sense for you, but there's no point in trivializing high-quality goods because you don't "get" them.
Buy $600 shoes if you want. But it's not always going to make economic sense to do so. I have a pair of $60 dress shoes that I've owned and worn for eight years now and they still look fantastic. I just don't wear dress shoes that much.
This is what the disagreement is over, though: empirically, do most people taking this route save money, or do they end up spending more money in hopes of long-term savings that do not materialize? It depends strongly on the shoe, wearer, and various failure modes (and how repairable / expensive to repair each of those failure modes is). In my own case, I've generally found that the expensive shoes fail to save money, because even though they're more repairable, the cost of repairs eats up any savings, vs. just treating shoes as a disposable good (might be different if I lived somewhere with lower labor costs; around here even a simple resoling costs $50, and anything more involved starts at $100+). That might still be worth it if you prefer the nice shoes, don't like unnecessarily sending things to landfills, or other reasons, but for me, from a strictly cost standpoint I've found it hard to come out ahead.
Shell cordovan is a bit unique amongst shoe leathers. It is valued by the people who wear it primarily because of the way it looks. Shell doesn't develop creases when you wear it, it develops "rolls". It also (at least in colors other than black, like Horween's famous Color 8), develops a patina that leather made from cow hide doesn't. It looks much better with age.
I just sold my late stepfather's 40 year old shell cordovan shoes for $100. They have seen lots of wear over the years, but are in great shape, and look amazing because of the afore-mentioned patina. That is why people pay that much for shell cordovan.
Another thing to consider aside from price and looks is that the design (how it is supposed to react on your walk) is fundamentally different from "cheap" snickers. For instance it's way more rigid and doesn't twist. For some it helps their walking, for others it's an hinderance.
I think your comment is completely unhelpful, because you're dismissing my point by simply repeating what the other person said. "You save money because you save money". No, if your shoe gets destroyed before you've worn them for six years, you're losing money. You don't seem to have addressed that point at all.