>When that net loss is averaged to units sold (which is a common metric for measuring financial performance in the automotive industry)
I agree the metric is common, but it is an invalid comparison for Tesla. The other car companies have mature product lines. The model S is their only production line, and they are spending money on development for the Model X and the Model 3.
If any car company were developing 2 vehicles for every 1 they have in production, then it would be a valid comparison. Comparison metrics have to be evaluated in the context of the company's overall life cycle. The art of valuing companies lies in choosing the relevant metrics to compare.
Tesla has lowered their current year estimates from 55,000 to 50,000 to 55,000, due to uncertainty about the Model X go live. And it hit their stock price... However, they have not changed their long term goal or time frame for get their factory to maximum capacity of 500,000 vehicles around 2020.