Tesla Motors has just stunned the carmaking world by taking 325,000 orders for its new Model 3 affordable electric vehicle within days of unveiling the prototype at its Los Angeles design studio. That is certainly an impressive performance — especially from a carmaker that has sold only 100,000 cars in its entire 13-year history.

But, aside from demonstrating the interest that exists in Tesla’s undeniably glamorous electric vehicle technology, what precisely has the US company’s hard driving chief executive, Elon Musk, achieved?

Let’s start with what he hasn’t done, which is to strike a very firm contract with those interested parties. A glance at Tesla’s website shows the relatively loose commitment they have entered into: paying a $1,000 upfront deposit to guarantee a slot on a waiting list. But this is not binding, and can be cancelled if the would-be customer desires.

Nor is there any fixed date by which Tesla must actually come up with a vehicle. While Mr Musk hopes to commence deliveries by the autumn of 2017, he doesn’t have to meet that deadline if the car is not ready. That, it should be noted, is a possibility. Tesla’s latest model — the Model X — was more than two years delayed.

Even the final price is not fixed. Mr Musk may talk about a $35,000 vehicle, but he is too canny to pin himself down until he knows how much it will cost to produce one.

That said, the customer’s main protection is Tesla’s own very public commitment to sell the base model at somewhere around this figure. Jack up the sticker price too much and the car’s “affordable” tag (and sales) will be lost.

What about using the reservations as a source of capital to complete the project? After all, it is not uncommon for companies to raise capital from would-be buyers.

Property developers, for instance, sell apartments “off plan” and use the proceeds to finance their construction. Then there are crowdfunding platforms, such as Kickstarter. Essentially, these allow people to pre-buy goods that they like the look of. Entrepreneurs then go out and see if they can be made profitably.

However, the problem with Tesla’s reservation system is that it does not deliver much of a capital injection. First, the $1,000 per head deposit is so small that it does not bring in much money. While $325m is not exactly loose change, it is a drop in the ocean when your capital expenditure requirements run to some $11bn over the next five years.

Second, the pre-orders are not just cancellable; the deposits that accompany them are also refundable. So the situation is more akin to the would-be customers granting Tesla an interest-free overdraft. Were the development phase to go badly, or prospective customers to lose enthusiasm, it is quite possible that a substantial chunk of that $325m could be yanked.

All it might take is a big glitch in the Model 3’s development, or the emergence of a sexier vehicle produced by one of Tesla’s rivals — say a General Motors or Toyota — which have now been alerted to the possibility of mass market electric car sales.

And even if it is delivered on time, the Model 3’s maths may not stack up for some buyers at the $35,000 base price. Some may be depending on federal subsidies worth $7,500 to buyers of electric vehicles. But these are cut back quite sharply after a manufacturer has produced more than 200,000 cars.

Tesla will also face plenty of practical questions about building the Model 3. No one can be sure yet whether battery costs can be reduced sufficiently to make the car’s low price tag viable. Then there’s the question of whether Mr Musk can produce the vehicle in the sort of volumes that his now-groaning order book assumes.

But, no matter: that is not the point of what Tesla calls “the single biggest one week launch of any product ever”. Its real purpose was to create a stock market “event” to encourage investors to focus on the scale of the potential opportunity. With the company still spending heavily on capex, and unlikely to generate significant profits until after 2020, it is these people who must ultimately foot the bill to fulfil Mr Musk’s dream.

Whether they continue to do so remains a question of faith rather than rational analysis. Tesla’s current market capitalisation of $32bn is almost three quarters that of General Motors, which produces 10m cars (including a competing electric car) against its annual 50,000.

Keeping that stock market spigot open will take not just excellent products and flawless execution in future. It will require all of the undoubted showman skills that Mr Musk has at his command.