He 'profited by' his experience/mistake. [=he learned something useful from his experience/mistake]
The book can be read with 'profit' by anyone who wants to understand how the system works.
We sold the house 'at a profit'. [=we made a profit when we sold our house]
(..) But let's talk about the Targaryen girl. You want to invest in her? I'm guessing the Iron Bank invested considerable gold in the slave trade. How are your profits now that Daenerys has freed all the slaves? The slave trade has entered a downturn, it's true. From what I gather, (..)2017 TvShow: Game of Thrones Title: The Queen's Justice Season: 7 Episode 3