$500 Million is less than 25% of $2.1 Billion.
Another: A German tear-down firm calculated the cost of building a model 3 at $28,000, all-in. So they would make a 20% gross margin on a sale of the base model when it's available. At the moment, you can't buy one for under $46,000.
The writer conflates gross margin profit and net profit. As long as the gross margin is healthy, Tesla will have a fighting chance. For example, if they average $10,000 gross margin on those same 500,000 reservations, they make $5B in gross profit $. That's enough to pay back all their debt and finance a large portion of their capital spending.
It's all about getting the production line running smoothly, which is why Musk slept on the factory floor for a couple of weeks.