What I tried to say is that legal action for debt collection is complicated and costly.
1. There is Fair Debt Collection Practices Act and state laws -- any violation of these can be costly to the debt collector or LC
2. Where to file the lawsuit -- borrower lives all over the 50 states
3. It takes time, maybe months, per loan
4. It might cost more than $35K for lawyers alone
I think the conventional ways of doing debt collection (i.e., calling, emailing, tracing) are more effective than legal actions. The considerable negative impact on credit history is another cost to bear by borrower, making it difficult to borrow money for a car or home, or to receive credit cards. The default status remains on the credit report for many years.
Of course, legal actions are always available to purse if considerations on regulations, time, and money have been taken into account.