Heh reminds me what happened during my last stint in retail.
We were suddenly left without a manager. Can't remember what happened, but manager disappeared.
My superviser at the time was temporarily placed on the manager role. My colleague, who was utterly brilliant, was placed in the superviser role (she was the only one who wanted to, but she really wanted it - youngest of the team, but by far the best for it ) .
They were both fantastic, especially my young colleague as superviser. She was on fire. Work became much more of a joy, everything was a lot more efficient and successful. Way higher profits too, everything felt much more relaxed all staff were doing well from it. It was a golden age.
We all felt for sure, that with it working better than ever, this would be made permanent and superviser and colleague would be promoted into those roles.
Nope.
After about 3 booming months, they brought in another manager, superviser was superviser again, and colleague was just regular staff again.
Young colleague was devastated. She worked so hard and rightly thought she had done a good job.
New manager was rubbish. Uncaring of staff and customers, over dramatic and - compared to the superviser and colleague - incompetent. Apparently she was already manager at another store so they just transferred her over, and brought in someone new externally for her old store.
I left just a few weeks later because she was awful. She accused me of stealing from the store - not to my face, not even going through official channels, but to my colleagues unkindly behind my back gossiping - due to regularly finding protein bar wrappers in the staff room bin after I'd been in there. It was my bloody lunch, from lunch time... and we didn't even sell those bars in the store (which is why she never saw me buying them, I'd bring them from home.)
All other staff, besides superviser (who still works for the company) quit within a few months.
Was just all so stupid. The store had it made. But promoting people is not what's done, apparently.