Also, their reorganization after each first generation of underhanded practices became recognized, otherwise attention could not have been as well diverted from the ability to leverage greed even more so than leverage the resources of the smaller investors.

Good historical reference sections on Wikipedia:

https://en.wikipedia.org/wiki/London_Stock_Exchange

>During the 17th century, stockbrokers were not allowed in the Royal Exchange due to their rude manners. They had to operate from other establishments in the vicinity, notably Jonathan's Coffee-House.

https://en.wikipedia.org/wiki/Philadelphia_Stock_Exchange

https://en.wikipedia.org/wiki/Tontine_Coffee_House

https://en.wikipedia.org/wiki/New_York_Stock_Exchange

NYSE of course is where lots of the money ended up from the international slave trade, and not just from sales in North America.

Seems to me that's what allowed NYC to take the place of London as the world's financial center, since the UK frowned on slavery much eartier than the US.

Also early 20th century oil might have been the only thing with as good or better return than slavery had generated.