There's a 'waterfall' effect of status signals. The upper class uses signal A to differentiate themselves from the middle class; the middle class catches on, and starts using signal A to imitate the upper class; the upper class moves on to signal B, to differentiate themselves from the middle class; the lower class use signal A to imitate the middle class; the middle class uses B to differentiate themselves from the lower class and imitate the upper class; from there, it cycles.

ABA->BAB->ABA

The upper class aren't worried about being mistaken for the lower class; that's why 'ghetto chic' exists, and why Zuckerberg wore hoodies. Conspicuous adoption of low-class signals can be a signal of high-class- for a while, till the rest of the culture catches up.

Usual caveats of 'this is a simplified model' etc.

Tell that to school children. "Daddy why can't i have an iPhone ? Everybody has one "