I am majoring in economics at university of Helsinki in the faculty of Social Sciences (valtiotieteellinen tiedekunta). It is quite hard to get in there.
I think fiat money system's advantages surpasses its disadvantages as long as the inflation is in control. Debt based system is not good one but fiat system is since it forces people buying right now instead of waiting eternally. Those who want to save money can do it in gold or silver, fiat money is not the right tool for it at least for more than a few years generally. Economy needs small inflation in order to function. On the other hand, if the inflation is too high it is also problematic. ECB targets 2 % inflation which is optimal in my opinion (not too high but not too low neither).
It is well-known fact that crypto is a pyramid but to say it is ponzi is not legit IMO.
All I said, the price of xmr should go up which encourages people buying the coin and thus increases the marketcap.
If the price is in bearish trend, it is rational to postpone the buys and if the price is going up it is rational to buy immediately.
The challenge is to find the exact rate of emission which goes along with the pace of adoption. Ideally the emission should be a little lower than the adotion rate since some long term bagholders might want to sell and it shouldn't cause volatility too much ideally so there should be constant shortage of the coins in the market in order to keep the marketcap rising.
Congratulations! Most academic economic tracks in the last 50 years or so have been slowly corrupted by truthiness and bias towards the status quo (after all, the universities manufacture the academics that justify the status quo for the populus). The argument that the economy needs a small inflation to function has been repeated ad nauseatum and rebuked just as many times. It does sound plausible, but it simply is not true.
First, inflation does not mean increasing prices. Inflation means an increase in the money supply, and increasing prices is just an effect. For example, since 2008, the USD went through a massively inflationary period, but prices did not increase because all the excess cash stayed far away from common goods. Indeed, the self proclaimed purpose of the FED is to create price increases in RE and stocks ("wealth effect"). I use the FED example because I'm more intimately familiar with the matter, but everyone else is doing the same thing (ECB, BoJ, BoE, etc). Bending the meaning of words like inflation only serves to hide the real significance of their actions.
Secondly, let's get to the meat of the argument. You claim that increasing prices are necessary to make people buy stuff, because otherwise they would not and the economy would collapse. This can be shown to be wrong with two simple examples:
1. If the prices for necessary goods (i.e. food, fuel) were decreasing, you would not starve, but postpone purchase until you really need it. Thus, you end up paying less for a larger utility gain. Decreasing prices of necessary goods encourages mindFUL consumption instead of mindLESS consumption (consumerism).
2. If the prices for leisure (unnecessary) goods (i.e. from sports cars to cell phones and boutique cupcakes) were decreasing, you would not buy less of them, but more. Since we assume they are unnecessary goods, you have no NEED for them anyway, so you buy them simply for hedonic/aesthetic reasons. If you can get more of them, you will. A very good example for this are tech products like smartphones and laptops. Their nominal price does not significantly decrease (but it does), however their price normalized for performance/capabilities decreases inversely proportional to Moore's &co. laws. This does not make people postpone their purchases "because they will forever be better off if they wait for the next generation", but instead makes people buy them more often.
As prices drop, at some point the gained utility from an upgrade is larger than the lost utility due to price, and that's when you buy it. This is valid for the next purchase too. This also price-discriminates buyers based on their early/late adopter traits, which is compatible with how prices work now anyway.
So, good luck in your studies, but make sure to read other schools of economic thought as well, because economics is far from an exact science. There are a lot of politics, a lot of manipulation and a lot of simply bullshit floating in the field.