This yard-sale model isn't really how the economy works though, people don't continuously bet 20% of their net worth. It's something similar going on though, I think a lot of these variables would seem to be explained by considering the lognormal distribution for personal wealth.

In a normal distribution, the shape of the distribution comes from a "random walk" left and right from a large number of steps of varying size.

In a lognormal distribution, on the other hand, the random steps are not additive but multiplicative: e.g you multiply the previous figure by a (Gaussian) random variable many times.

This seems to reflect economic reality that people make decisions proportional to the scale of their current wealth. If I make 10k, it would take 2k extra to entice me to a different job. If I make (or lose) 10% on an investment, etc. It's all multiplicative.

The lognormal distribution also has a fatter "right tail" than a Gaussian, which is what we see IRL.