You have forgotten to factor in many things.

What will these differently-housed individuals do for income? Where will they work?

If they are in the middle nowhere as you claim, how will they physically get to their job? If they have to drive significant distances to get to these civic centers, then you have grossly underestimated the percentage of their income that would be slated for transportation.

Let's do some math! Your fantasy $20k trailer with your parameters, with an estimated $1000 initial cost for service connections would wind up being a bit more than $27k after APR adjustments. Calculator That winds up being $222 per month. What a steal!

Federal minimum wage is $7.25. Taxes are a thing, so $7.25 turns into $6.52. An individual would have to work a bit more than 34 hours to afford just the dwelling.

We are assuming that this person is healthy, with nothing to prevent the individual from working.

Will this person have electricity? $122 or 18.7 hours Will this person have clean water? $18 or 2.76 hours Will this person require clothing? Will this person have healthcare?
Will this person take any prescription medication? Will this person have a dental plan? Will this person pay for transportation (the vehicle, insurance, wear and tear, gas, and incidentals)? Will this person support additional family members who are unable to work (children, elderly, injured, disabled)? Will there be air conditioning and heating in this $20k trailer?

What will this person eat?

Going beyond the absolute basics: What will this person do for entertainment? One cannot honestly expect a human to live without some form of stress relief. Will this person have access to the internet? That is required for resume submission for almost every job. What will this person save for retirement?