I don't have an answer for you, but Reminiscences of a Stock Operator is required reading for anyone interested in the history of securities markets. It's fictionalized autobiography of a legendary trader in the 1920s. It could have been written yesterday or a thousand years ago.

https://www.amazon.com/Reminiscences-Stock-Operator-Edwin-Le...

"In the olden days it was relatively common for people to begin in the mail room and work their way up to CEO. Exchange floor traders would frequently start as clerks and runners."

One of the most famous examples: Jesse Livermore[1], whose Reminiscences of a Stock Operator[2] is one of the most recommended trading books ever. (I recommend it too. It's awesome.)

He never climbed the corporate ladder, but did start out writing prices on a blackboard for a brokerage. He went on to become a hugely successful trader, only to lose it all, and repeated this cycle many times.

[1] - https://en.wikipedia.org/wiki/Jesse_Lauriston_Livermore

[2] - https://www.amazon.com/Reminiscences-Stock-Operator-Edwin-Le...