I doubt that public school teachers can better prepare low-IQ youths for these jobs than the employers can themselves. Subsidizing apprenticeships would likely be more effective than spending ever-greater amounts on special education.
The kind of students we are describing are a tiny percentage of the population of special education students. Where I teach, most student who receive special education services are in general education classrooms for most of the school day. Many of them continue on to college or post-secondary vocational training.
US Schools are required to work with high school special education students and/or their parents in order to create a plan to transition to life after graduation. This takes the individual strengths, challenges and interests of the student into account. There are any number of things that might go into these plans, and any number of community partners that might be involved.
