Just using it as your personal keyboard in normal day-to-day settings isn't nearly the same. Because you're not actively showing it off.
Apple users don't wear white ear buds to signal to one another, they do it exclusively to signal to people who don't have it that the apple user can afford product and symbol greatly in excess of the person.
Same with mechanical keyboards. The signal there is to people using shitty 20$ dell membrane boards, and who see those beautiful machined aluminum boards and custom caps and feel jealous. The signal is about demonstrating you have more than someone else.
When two people who have similar things are showing it off, that's not signalling, that's talking shop.
I think the average $20 membrane keyboard user is looking at these things and thinking, hey, that looks funny, assuming they notice them at all. Most people don't know that it's possible to spend $100, let alone $400 on a set of keycaps.
Or, you know, they're not interested in "signaling" anything, they're wearing them because they're the free ear buds that came with their smartphone and they're listening to music or making a phone call.
Alternatively: Or you know, mechanical keyboard users aren't interested in "signalling" anything, they're just using well manufactured accessories featuring high quality processes and materials.
Or, alternatively, since I'm currently on an iphone SE, "oooo, what is wrong with you, why don't you upgrade to a new phone?!"
Another comment mentions functional utility. Put me in the camp that resents the desire for functional utility being misconstrued as social signaling
I never argued that mechanical keyboard users were interested in signaling anything -- but I'm sure a similar dichotomy applies. Some are interested in signaling. Some are interested in them because they're good to type on. The analogy only goes so far, though, because mechanical keyboards are an extra-cost purchase, while iPhone earbuds are free pack-ins which most people don't consider to have particularly good fit and sound quality. If I'm interested in a well-manufactured accessory featuring high quality processes and materials, I may buy a mechanical keyboard, but I will probably not stick with the damn white earbuds. If I'm wearing an audiophile brand of in-ear monitors most people won't recognize out in public, am I still doing it to "signal"?
Or... we just use them because they are there. I use Apple products, also bought a pair of AirPods just a few weeks ago, not cause I want to signal I got money, but because the things are pretty nice to use as headphones. I have 6 pairs of headphones, and while these aren't perfect they fit the overall pro/con situation well compared to even stuff like Shure headphones.
Sometimes a spade is just a spade. Sometimes people really do just buy something for its utility. Even when we may not see it personally. While I'm sure there are BMW drivers that buy them for prestige or signalling, I am also quite sure there are drivers that bought it because they like the overall BMW experience, garage visits included (I can't resist sniping on this for my one buddy).
Just accept that there are Apple users that not only prefer, but are willing to pay the "tax" of not using Android or other phones.
Try buying earbuds. They are either $40-60 or shit.