In theory, Vicente and Rory's idea could work very well initially. However, two potential scenarios could unfold once the people realize the danger of causing trouble in the establishments guarded by their group.
First, there might be fewer incidents, which would cause their financial returns to plummet. The second would be more trouble, escalating into a higher-level crisis which would hit them.
In the former case, Vicente's group could continue to operate only by adjusting the monthly fee. In the latter case, they would face increased work and, therefore, more income.
That was because stronger enemies usually had more resources, and as the risks increased, so did the returns.
In this situation, they would either be able to withstand the pressure or not, which would lead to their group's extinction, or be at peace along with a consequential increase in the price of their fees.
Vicente had already made it clear that this would inevitably happen.