... joining the discussion late.
To address the OP, are there two sides to your question? The Caldari infodump is about their financial system. But it seems you are also wanting to discuss cultural differences as well. Well, they have to be intertwined so maybe two sides of the same coin? (pun intended)
There are lots of tidbits that infodump tells us about the Federation's financial system:
- "independent" banks... largest remnants of the legacy finance system that existed under the Federation [Gallentean banks are not under corporate umbrellas]
- ...exchange rate with Federation currency... [single currency system, subject to currency market, unlike Caldari fixed rates (a la Chinese)]
- Unlike in the Federation, there is no government-backed insurance for any sort of savings account in the State [Federation has social protection for its citizens, a very Western model]
- megacorporations depend on the independent banks for their well-being, especially Caldari Funds Unlimited, which acts as a “bank of last resort” in the State, similar (but not nearly as powerful or robust) as the Bank of Luminaire in the Federation [Luminaire, as an epitomized Gallentean bank is more powerful and robust, likely due to being free of megacorp control, as in the State, can be more diversified and invest in competiting interests]
- Unlike in the Federation, there is no government stipend to bolster savings for retirement [another socialistic cultural theme, government as protector for the people as a participant in the open financial market, not owner of it]
- While the Caldari economy has been characterized as an unregulated ultracapitalist melee by Federation critics [hinting that the Gallentean system is more regulated and more socialist, which makes sense from what we know of the Gallente cultural]
IMHO:
All of this hints at a market in which megacorps are just as free to proliferate as in the Caldari system, but with the understanding of how cultural differences affect the way Federation megas are run and controlled. Caldari = group oriented, success for the group at expense of individual (culture protects individuals to some extent), honour tied to service to the group. Gallente = individualistic, success for the individual over the group (regulations protect the group), honour tied to personal liberties and their preservation.
Gallente megas don't have physical regions of control like the Caldari (except maybe on stations), but I imagine they would have anti-collusion/monopoly regulations like most RL western societies (again based on governm't protection for the individual). Instead they would have market shares and exert control through marketing and persuasion. Gallenteans would have the consumer-based society type of the US with some of the European socialist leaning, contrasted agains the employee-citizen model of modern day Japanese culture.
TL;DR megas should exist everywhere (or at least as much in the Federation as in the State), but are simply run differently per cultural differences.