I think we can also agree: A) many behaviors we associate with gender differences are socially constructed, B) spending behaviors in particular are frequently socially constructed by gender, and C) most people are capable of personal introspection about how to at least reduce spending on items that they are socially motivated to buy.
The issue at point in this thread is pushing back on social pressure to spend more than we need to in gender-specific patterns.
So the thing I still can't get past is that we're still all Sneetches. We are all part of a tribe. And so we naturally all want to (a) demonstrate that we fit into that tribe, and (b) establish the highest social status we can within that tribe. The former protects against being cast out; the latter provides the best choices of food, shelter, and mates.
In our current society, we distinguish ourselves with things like beauty products and big trucks. In other societies, it could be tattoos or piercings or super-elongated necks or lower lips. In Victorian times, for women, it was who had the teensiest waist/biggest bustle/palest skin. If we were tropical birds, it might be the best possible mating dance to outshine all the other birds.
None of those other things make a lot of sense to us, because that's not our culture, and so that's not what we value. But we do have cultural values of our own, and whatever those are, we devote -- and will continue to devote -- what seems like illogical and unnecessary resources to those values to establish our place in the social order. Maybe in 20 years it won't be big trucks, but the coolest electric vehicle. If that happens, then we won't be spending so much on big trucks, because it's not about the truck. But we will still be throwing stupid amounts of money at the coolest EV, because we'll still be Sneetching our way through life.
I think the true value of this place is that we establish our own tribe, with our own values that are different from the primary culture we live in. It allows those of us who've never fit particularly well into that primary culture to feel like we fit somewhere, and it provides an alternative to those who aren't particularly happy within those society-set expectations. It shows there is another way to be happy and secure and content, without having to throw around money we don't have on stuff we don't need.