You can't get student loans discharged in a bankruptcy, but you can still default on them.
What's the point of preserving a credit score to get a nice apartment if you can't afford to move out regardless? What's the point of preserving a credit score to buy a nice car if you can only afford a used beat up car to begin with?
Garnishment isn't an issue if you have low wages either. Wages can't be garnished if you make under a certain amount of money.
Living with poor credit is a challenge, but it's not insurmountable. Tens of millions of people do it in this country every day. Young people with college educations won't be making minimum wage for the next fifty years. Eventually opportunities will come. When they do, people can start paying the loans, exit default, repair their credit and get on with their life.
I think people in a bad spot should really ask themselves, "What value does a high credit score really have right now?" If you don't have a high enough income to access credit, then a high credit score is worthless. I think there's a strong argument to be made that people can have a higher quality of life at low incomes by strategically defaulting on their student loans.