The embedded assumption is that current demand is sustainable, rather than simply a reduction in a multi-year fanatic backlog.
Embedded inside that assumption are a lot of assumptions about ramps in production with consistent quality and finish, and lack of EV competition.
I personally disagree that Tesla can maintain production and quality at these levels without needing more financing, but the verdict is definitely not in yet.
But really what you're implying is, when Fremont is a closer to full produciton, each Model 3 will net a loss. Best engineers say no. https://www.cnet.com/roadshow/news/2018-tesla-model-3-munro-...
Even Tesla's public financials show they lost more money, when they made less model 3s.