Why Hard Work Doesn't Get You Promoted
Hard work signals competence at your current level, it doesn't signal readiness for the next one.
Promotion decisions are formed from a different set of reads: can this person operate at higher authority?
Do they already move, speak, and own space like someone at the next level?
If the signal reads "excellent at what they do now," the room files you as irreplaceable where you are, not as someone to move up.
Hard work proves you belong where you are. It doesn't prove you're ready for the next level. Those are different signals, and organisations respond to them differently.
You've been told the answer is to work harder. That wasn't wrong advice for reaching where you are. For reaching the next place, though, it's the wrong advice, because the mechanism there is different.