Habeas corpus applies to illegal detention. After an arrest, you may be detained even without charges for a "reasonable amount of time". In most cases, this will be 48-72 hours depending on the state and your circumstances. After that "reasonable" period has passed without charges, your detention would then be illegal, and habeas corpus would be the perfect remedy.
So why isn't it used?
The answer is simple and twofold:
1. These people don't know to do that, let alone how.
2. They don't have the money to pay somebody who knows to do that.
The final, uncomfortable answer here is that most of these people are actually guilty. If they filed the writ, it would only serve to speed up the actual filing of charges. This could be seen as a good thing, but why would you take the few thousand dollars to file habeas corpus when your family is now suffering because you aren't working anymore - and because you committed the crime you aren't going to be working for some time to come. So might as well wait out the period anyway. Is it fair or good? No, its brutal calculus.
IIRC, you can't get free legal representation for habeas actions?
So, firstly the prisoner needs to be very legally savvy and have access to things like pencils, paper, law library etc, which is no given, especially if they are in a county jail which is usually far more restrictive than prison.
Then I believe you would have to exhaust your state habeas first before you can file federal habeas. State county courts have judges who rarely know the law and will never have seen a habeas action. So when you file it, they'll probably spend a year pushing it down the docket (especially because you're in jail) before finding some random reason to dismiss it.
You'll get more educated responses from federal court, but filing there is a little bit harder and the cases take just as long.
Habeas could easily be a multi-year, perhaps up to a decade to litigate through to disposition, especially for someone acting without a lawyer.
No, as a society we apparently don’t really care about these inmates. The social justice movement has chosen plenty of questionable causes, but neglected ones like this one.
The social justice movement has focused on prisoners, and especially on reducing incarceration and allowing former prisoners to transfer back to society successfully.
The progressive DAs elected a few years ago prioritized decriminalization and deincarceration, and for formerly incarcerated, movements such as 'ban the box' (prohibiting employers to require info on past inceration) and restoring voting rights have also been priorities.
There's also focus on the 13th amendment of the Constitution, which has an exception for incarcerated people to be used for forced (slave) labor.
