Yakuza and extra-legal contract enforcement

BoingBoing's interview with Jake Adelstein suggests that one of the Japanese Yakuza's main lines of work is in provision of extra-legal contract enforcement and dispute resolution:

In fact, lots of normal people go to the yakuza to solve problems. In Japan, civil lawsuits take forever to get resolved, and even if you win the lawsuit nobody will enforce it — if a guy owes you money but won't pay up, police officers aren't going to go out there to seize his assets. If someone owes you money or you're in a civil dispute, the yakuza will take half of whatever they can get out of the person who wronged you. But at last you get half, and it's fast.

...

Here's the thing: Japanese people kind of like the yakuza. They admire them. There are movies about them, comic books about them, there are fan magazines... they're part of the culture. They promote traditional values.

One of the reasons Japan has low street crime rates is because these guys are very good enforcers. In the neighborhoods where they're running businesses or collecting protection money, you won't see people getting mugged because the yakuza don't want people to be afraid to come there and spend money. They are a second police force and in that sense, and perform a valuable role in Japanese society.

Inefficiency in state provision of contract enforcement and security promotes competition?