The federal government tracks all student loans, they know very explicitly how many people qualify.
If you're making income based payments, and you have low income, the debt grows over time because the payments aren't even enough to cover interest on the debt.
2.5 million people qualified for this plan, one of 5 that were put in place.
The plan was largely targeting dropouts, because they tend to be most trapped by loans. They don't get any income benefit from a college degree, and tend to have lower paying jobs. If you're doing income based repayment at minimum wage, it's possible for your loan principle to grow continuously.
I'm not saying it's perfect, but it definitely would have helped people.
Because there's another mass shooting every couple days. It's hard to care about why one dude did something crazy 7 years ago while bullets are still flying. People are much more focused on trying to stop the next one.
There are some good answers here, but I would also note that because the legal system is adversarial, continued investment can go a long way towards a desired outcome. If you can afford a parade of experts, huge amounts of gathered evidence, and contingency plans researched and prepared by dozens of lawyers and paralegals, you'll do better in court.
It's an arms race, so the "best" lawyers have spent the most on arms. That also means that even the worst lawyers have to invest a lot to keep up.
It would make a difference to the people living there who are too poor to leave.