Well I guess it's not the wooden box of a speaker that costs $2000-$30000 (normal price range for consumer Hi-Fi speakers). Replacing the speaker drivers would be more like replacing everything within the body of a car.
Justification isn't really a thing in that market (see also: luxury watches).
My friends who are into hi-fi/audiophile stuff who value accuracy typically do go for studio monitors or similar (e.g. Harbeth) vs. stuff like Wilson Audio. Some of them still buy fairly woo-woo stuff like spendy cables even though they might know better, but at least they don't go in for the pure scam stuff like Shakti Stones or directional Ethernet cables...
I genuinely wonder the same actually. Seems like there would go even more engineering into making a speaker that is "true" and not coloring the sound as one expects from their monitors.
There's plenty of real engineering but it's only engineers that can differentiate the heavily marketed and absurdly marked up snake oil things from what's real. DIY people share honestly good designs that are underperformed by speakers/amps that cost 10x or more.
You're right that it's about a space, or a field, which is in the name, but you're wrong in contradicting the other poster. The near field is determined by the radiating surface, the front baffle of the speaker. Room height line arrays for example have a large near field. Near field speakers are those with tuning designed to be flattest when listened to inside the near field. The link you posted is confused and misleading, which is unfortunate since they dressed it up as some kind of "myth busting".
It's easy to trick people into overspending on audio gear because you can use their love for music and their subjective biases and their egos against them. It's like the perfect situation for slimy sales tactics.
Beware, if you're spending $10k+ on consumer hifi speakers you're almost definitely getting ripped off.
It costs only a few thousand at most to get the raw parts and materials to build truly world class speakers (quality-wise) that are loud enough for any normal living space. Maybe not for a concert hall type space, but that's not consumer hifi anymore.