From my understanding, when people literally have no money to pay for rent, there is usually an option to do a few hours of easy work helping at the shelter every month in lieu of money. And it's difficult to get an accurate percentage of people on the streets that are suffering from severe mental illness or drug addictions. Sadly, the ones that you see suffering from serious unattended medical problems are often the ones that need help the most, but are not aware due to their state of mind.