>I'd like to see some hard data and sources for this assumption,

"prove that this illegal thing would be good systematically at a macro-economic level when it being illegal has not shown to be good"

  >this assumption, it's quite a big one and since you started the argument with the unrealistic view that those jobs are only stepping stones to better ones or performed by youngsters with access to their parents' home

Fuck, ya got me. Let's try the opposite: lets give economically vital careers to homeless babies... that makes a lot more sense.