Generally speaking, you can't generalize vehicle production with new companies, or even old ones. Vehicle production is extremely complicated and expensive. Minor quality errors lead to increasing delays and costs.

Famously, GM used to spend ridiculous amounts of time and money to fix cars coming out of some of its plants. It wasn't uncommon for some cars to be incapable of being driven out of the plant. The more cars they made, the more errors, and the more time and money spent on fixing them. This was a major factor in the development of the NUMMI plant.

What brings cost down is increased quality, reduction of waste, and increase of speed. If you don't have all three you aren't gonna save money.