You're right, but (IMO) only looking at half of the whole.
Tesla is spending a lot. More than they earn. Whatever back-of-the-envelope profitability
model you attribute to their car making operation to differentiate marginal-operational from capital-investment costs, it does not add up to anything like enough to cover all costs. They cannot cover costs from free cash (as you say) which means they need capital coming in (as you say), debt and equity.
But, this doesn't mean they are selling elonmagic. No one would expect a car company to bootstrap, grow from cash flow. The place they expect to be is cash-hungry. This is what accountants are for, figuring out if a company is headed towards profitability when free cash flow is not an indicator.
The whole idea is that Tesla will be gradually capitalized to the point where it is like GM or Toyota.
Where elonmagic does come in is the same place startup-magic always comes in. It's novel in the auto industry. But, it's bread and butter on crunchbase (or here).
Does this company have the potential to create a large, high margin business. The accountant will have a harder time telling you this, and so will annual report readers. It's like answering the question Will Facebook manage to build an advertising business like Goog's? The answer turned out to be yes, so FB is worth a lot of money. Valuation of FB at IPO time was essentially the aggregate investor's answer to that question at that time.
Elonmagigic plays a big role in that 2nd part, unavoidably. This seems reasonable and to me.
Accounts are accounts. Sometimes the story is simple, and accoutns tell a simple story. Sometimes the real story is there, but takes context, digging and smart accountants to tell properly. Some important parts of the story are not in the accounts, like the fact the Tesla can apparently produce a faster supercar than anyone at 1/4 of the cost.