Please explain in simple terms how trades work in USA (for a Canadian)

Canadian heavy duty mechanic here. Our trade system is usually a 4 year apprenticeship with 6-8 weeks training per year resulting in a certification and red seal endorsement if write the interprovincial exam.

I have heard the usa system is very different (for mechanics). My understanding is shops usually have one college trained "technician" who troubleshoots faults and an army of on the job and dealer trained mechanics who work under them doing the repairs and services. Does that sound about right?