Of course people could have no issue building an ANSI board. But since it's custom, what's the point of making something custom that doesn't fit you? It's definitely not just "an aesthetic concern", it's usability - if someone is used to hitting their tall Enter for years, why should they suddenly relearn that for no benefit?
You don't need to be a rocket scientist to get used to not hitting a tall enter. If people can swap to layouts like ortho, anyone can just learn to press their enter key a little differently, it's a completely ridiculous argument to even make to anyone who's used more than 1 keyboard in their life. If you think being able to participate in every set buy and/or spend less money because of ISO being ostracized into smaller kits which becoming increasingly popular is "no benefit" then that's perfectly fine but I assume the argument wouldn't be made if people didn't wanna buy the sets.
Also, you realize ISO has one more key, right? That key is kinda important for keymaps in languages other than English, and having it on a layer is very annoying.
I live in an ISO area, I do realise. TKL has 28 more keys than HHKB does, what's your point? It's about the benefits outweighing (or not) the downsides, of course it's gonna be personal preference.
So please stop talking like everyone should use ANSI or get out, because it's nonsense and you're dismissing tons of people only on the basis of "what I use is widespread here so everyone else can suck it". Do you apply that logic to other board sizes than you use, to ortho, splits, different USB ports, ...?
I'm not talking like everyone should use ANSI or get out, I use plenty of ISO keyboards, be it for aesthetic or because I find long shifts completely useless (extra stab, 1 less key, etc) hence I like splitting the left one in smaller boards in addition to the right one. I'm actually a big advocate for keeping basic ISO support in most core kits - this being a fringe case because they don't have moulds, no moulds, no keys) if for no other reason than it benefiting me and my preference - I'm not dismissing anyone I'm merely offering up advice and being realistic in that
anyone can make the change if they really want to and if they think that will benefit them in the long run.
PS: My logic cannot be extrapolated to whatever else you referred to, for example the fact USB-C is categorically superior to mini/micro has nothing to do with what I'm arguing here and the fact you misinterpreted it that badly is quite concerning.