Problem: in game design you get to ignore all sorts of real-world constraints you can't ignore in the design of an economy.
For example, yeah, it's incredibly hard to get a business started. If, in an RPG, to get a character past level 1, you had to out-compete all the established characters, a lot of people would fail in the early stages. It's hard to find a fair way around that in the real world. Things like economies of scale and interest weren't designed into the economy. They developed for good reasons and have helped us become more prosperous and use resources more efficiently.
It's true that there are some cheaters, people that use their powerful position to influence the admins and change the rules. And there are some rules that hurt small businesses beyond what's necessary. Employer-based health insurance, for example, benefits large employers over small ones to a stupid degree. But I think you could fix all the problems that can really be fixed, and even simplify some laws, and it would still be hard to start a business.
On the other hand, seriously handicapping large enterprises in some industries might have awesome consequences. I'm thinking agriculture and mining here, with the consequences being more local agriculture and more efficient use of the land that's currently wasted on exurban subdivisions.