While there are some robotics involved, there is a lot more hands on labour than one would think, even the Mainline ($1) cars.
Unfortunately, the process is proprietary and confidential. A lot of toy (and other consumer product) companies deal with some very sensitive licences. So, no cameras are allowed in the facilities. But, if you watch enough "How It's Made", you can figure out the process.
I am sure there are some bootleg videos out there, but nothing official.

