These reasons are why only banks supported by gods can compete in the industry at all. But all they can do is compete. They can't match banks established by the church of wealth at all.
Just the ability of the priests of wealth to identify counterfeit money and judge the value of people when giving out loans is enough for the church of wealth to remain dominant in the industry.
If he can invent a communication system that rivals communicating with altars or is even better than it and have a business partner in the banking industry who relies on this technology, this partner will be able to compete with other banks supported by gods.
Of course, this bank will only be able to compete. It won't be able to dominate the market at all. That is good enough for him. And if he remains as the hidden partner, he will be able to reap the rewards in secret and avoid the attacks of all the enemies that this new communication system will create.
