IDK a pair of $250 racing flats once a year seems pretty minimal compared to the cost of a lot of other things people spend on running, especially the demographic most concerned with buying vaporflys.
These include:
-- Races, particularly ones that involve travel. Particularly big marathons like Boston, New York and Chicago. 200-300 dollar entry fee, a flight, a couple days hotel, that certainly adds up. Outside of the occasional out of town race for a marathon or a half, I mostly race locally which is comped by my race team, but if I didn't that would be $30-40 dollars a race even locally.
--A running coach. While certainly not necessary, 90% of the age group competitive and better runners I know work with a coach or have at some point. Hell, I work with a coach. I like my coach, but I pay him $150 dollars a month. I used to coach myself and improved for a while, but it's hard to be objective about yourself and I definitely get value from a coach. And I can afford it, so I have a coach. That adds to the expensiveness of the sport though.
--Trainers. I run 2500-3000 miles per year and get ~400-500 miles out of a pair of shoes, which I think is pretty typical (I know some people will claim to get 1000 miles out of a pair of shoes, but a lot of my running friends think you need to replace after 300). Some people run a lot more than I do. That's 5-8 pairs of shoes a year. You can get cheap ones on sale and I usually buy last year's model, but even so that's maybe 500-800 dollars a year in trainers.
--Physical therapy/sports medicine/whatever. Everyone gets injured and goes to the PT eventually. Sometimes people get extra blood tests that aren't covered by insurance to ensure their ferritin isn't off or whatever. Some people go get sports massages or go to the chiro to deal with a weird niggle or get dry needling. Some people use inside tracker. Anyway, additional costs for care from the PT is a pretty routine and typical expense for anyone who trains at any kind of semi-high level.
--Consulting with a sports registered dietician. I know of several runners who have felt the need to dial in their nutrition.
--Strength coaches, particularly coming back from injury. A lot of runners I know have done this.
--Recovery stuff, like cryotherapy or normatech boots. Not necessary, but more common than I would anticipate given how expensive all that stuff is.
--Fancy GPS watches, a ridiculous amount of athletic clothes, and so on and so forth.
Still cheaper than cycling, skiing, triathlon, or any number of other sports, but still a lot of ways you can sink money into running, even when doing it recreationally that all seem to add up to a whole lot more than buying shoes that are 150 dollars more expensive than typical racing flats.