[throwawayzRUU6f]

Because those better yields are there for a reason. That reason isn't lack of intermediaries, it's high inherent risks.

Economy has a risk-free rate of return, that of 1-year treasuries, at 0.05% currently. Anything above that involves risk. A rate of return of 7%/year means there's 7%-0.05% chance of the instrument being worthless after one year, ~14% chance of it losing half its value, ~28% chance of it losing a quarter of it's value, etc. There's no free lunch, and there's no financial arbitrage

[cmuguythrow]

Two economists are walking down the street and happen upon a $20 bill lying on the sidewalk. The first economist says, "Look at that $20 bill." The second says, "That can't really be a $20 bill lying there, because if it were, someone would have picked it up already." So they walk on, leaving the $20 bill undisturbed.