>>18522913
Because skeleton has been a way for mid-level brands to "look high end" to people who don't know any better.
Get an ETA, hollow out the bridges by machine.
Put the hands back on with no regard for contrast and legibility.
Boom, plebs now think it's some kind of impressive watch because "woah you can see everything it looks so precise and detailes it's like lace but made out of metal"
Open heart in particular since Seiko, Miyota, ETA and (iirc) Selitta offer ready made open heart movements.