The main reason this drop-out culture is so unsustainable is because in most places I have seen they have not built any real infrastructure to create or sustain a society, they exist entirely as parasites. A small group of drop-outs parasites off of others in their subculture who have jobs and pay rent. That is how they find places to sleep. They feed themselves not through growing their own food in communal gardens, but by shoplifting from the local supermarket. The skills encouraged and honored in these societies are solely skills of parasitism.
People brag about what they stole or how they hopped a train or what scam they pulled.
I've never heard people in this drop-out culture brag about being able to fix a car or build a house or create an irrigation and drainage plan. As much as we all love being entertained, we can't have a revolution of poets because someone needs to know how to fix the toilets after we win. In fact, their very lifestyle of acquisition through shoplifting does not encourage workers to liberate themselves or take control of the product of their labor. Shoplifters do not seek to abolish Capitalism, they need it intact. They need stores to steal from and trains to hop, they just think that other workers should have to drive the trains, make the products, and grow the food while they couch surf and play music.