Final answer:
The term 'echelon' is the appropriate word for the given sentence as it suggests levels within a hierarchy, which correctly describes the progression in a company's management.
Step-by-step explanation:
The correct word to use in the given sentence is 'echelon,' which refers to a level or rank in an organization, profession, or society. The sentence would thus read: "Over the years, hard work and unstinting devotion to duty have raised me from one echelon of company management to the next." A 'paucity' refers to the presence of something only in small or insufficient quantities or amounts, which does not fit the context of the sentence.
The subject addressed here is related to the understanding of vocabulary and context within English language comprehension. The use of the term 'echelon' is particularly relevant as it signifies levels of advancement within a structured system, such as a company's management hierarchy.