In large corporations promotions are frequently way more a product of “playing the game” than of doing work that’s related with your work. It makes a tiny bit of sense from the point of view that sometimes promotions involve developing a network of contacts and knowing how to use it. But only a tiny bit…

In small companies, promotions are very very rare, as the organisation doesn’t have a big structure.

Also, “objective criteria” is, at least in my experience, pretty nebulous, which make it quite subjective in practice