It's not simply a question of math. The project is different now. It has more structure. And we have the DIF, so direct proposal funding is not the only option and in many cases IT IS NOT THE PREFERRED OPTION. Most of the people who are attracted to the proposal system are either amateurs or sociopaths. We need to keep the fee high so that they feel the appropriate amount of pain when they create a proposal.
@xkcd, how come you don't comment on DashCentral?
First year economic study says the concept of supply and demand is math. The current system has an unknown demand side because you choose to have the entry fee fixed at an arbitrary number. The equilibrium can not be discovered in the current system.
Let's just say, for arguments sake, that your assertions are at least partially correct. Perhaps then the optimum fee is higher than 5 dash? How are we going to discover that price? - by randomly choosing a higher number?
You may assert that the current system clearly works. After all, the budget this month was almost full, leaving only 13 dash on the table. This also means that coin inflation will also be maxed out; the coins requested will be created and distributed from the superblock. Conversely, if a lower fee leads to more demand that the system allows, those proposal fees will be burned, leading to increased coin scarcity. I mean, even if MNOs vote entirely for scams, the inflation can not go beyond what is already maxed out, it's just not possible.
More so, let's just say the proposal fee is 10 dash and the treasury still maxes out, that too creates more coin scarcity. In your assessment, it would also increase the quality of proposals. So while you're busy looking at the potential downsides, you're completely ignoring the potential upsides.
Assuming demand is there, increased coin scarcity pushes the price up, which means all stakeholders gets more bang for their buck.