Lately I been thinking on the economical values as well socio-political settings on the Mushroom Kingdom and the world is located is a mere dystopian nightmare that is controlled by a bunch of corporations and there is no competitive impulse in the market, we can even think there is an oligarchic system implemented as it seems the world is controlled by the same families despite the different ages.
This is just a mere crazy theory, as there aren't really a set of cannon towards the games but rather there is a consistency to make the characters seem that they own brands around the different regions and what assets families control.
One clear example about a monopoly in the game is how much the Kong Family influenced the commercial development of the Metro Kingdom, it seems not only from the name the inhabitants have which is New Donkers but also from business that have their names such as Diddy's Mart or Dixie Street, there is no real way that the Kong Family wouldn't execute the influence if they didn't control their assets and avoid paying taxes by claiming their taxes and send them off-shore.
That is where the Mushroom Kingdom comes in, through the different incarnations starting from Mario RPG to Super Mario Galaxy seems to be the point where the money from all around the globe tends to go, because it does seem to thrive from a powerful economy in which taxes doesn't seem to be an issue as there are luxuries almost everywhere, such as racing fields as they are seen in the Mario Kart series and the hospitality industry that shelters golf courses is booming.
The political structure of the Mushroom Kingdom is based on a centralized monarchy, which leaves all the powers related to Peach and giving her almost an absolute rule on what decisions to take towards the growth of her Kingdom, which she could simply ignore any foreign pressure to reveal the source of income from any foreign investors as if she has any involvement in the business of any of the other kingdoms around the globe.
Peach as a ruler and as an investor she would benefit a lot from the income that her Kingdom receives, because that tax revenue that could be collected by the other Kingdoms but that their corporations tend to do business outside means that Peach would be receiving the revenue that could be used to improve infrastructure of other Kingdoms.
The infrastructure of the different incarnations of the Kingdom is quite concise with the representation and it gives an idea that much of the problematic with international relations is involved towards politics and economical affairs, if we diverge on what we had seen on the games we can maybe infer that Bowser's several attacks on Mushroom Kingdom hasn't been motivated by financial reasons rather than being in love with the princess, because a coup on the monarchy means that he could gain assets towards what Peach has.