There's a reason why ex-military are disproportionately homeless. These aren't lazy people or people who don't know the meaning of hard work. These are people who have sometimes serious mental health issues (e.g. PTSD, depression, alcohol addiction, etc) which make holding a job difficult or impossible.
20 hours of work might be difficult for many. Also who is going to live in a dorm with addicts, people with other assorted mental health issues, and people with various criminal records? There's a reason a lot of homeless people avoid "shelters," those places are sometimes MORE dangerous than prison (wanna get stabbed? Because going to a homeless shelter is a good way to get stabbed).
Honestly there isn't a "one size fits all" solution to homelessness. All homeless people are homeless for different reasons. All we as a society can do is start dealing with SOME of those problems one at a time.
If you do want to do the dorm thing then security has to be priority number one. For homeless people the streets can actually be safer than living with some of their peers.
The issue with the homeless isn't that the jobs don't pay enough to keep them off the streets, it's that they lack the mental faculties to hold onto even the most basic of jobs. Alternatively they're just exploiting suckers for easy money- a reality that many feel-good white evangelists like to pretend isn't a significant reality.