Tesla has something like 400,000 pre-orders for the Model 3 and is now delivering the $44,000 premium version. The price can rise to $60,000, once various options are added.
That's not crazy far from the cheaper trim levels of the Model S sedan that have sold in Tesla history (the least expensive Model S is about $75,000). So Tesla's first Model 3 buyers aren't hugely different from its prior customers.
Knock the price down to $35,000 and you open up the mass-market. But you also make less profit per car. And you cut into revenue. All negatives for Tesla in its current predicament. So Tesla could continue to hold off on producing the base Model 3, perhaps so that it preserves a $7,500 federal tax credit for wealthier customers.
That incentive phases out after Tesla sells 200,000 vehicles in the US, and because it's a tax credit, it's of use mainly to richer folks who might actually owe the IRS something on April 15.
Tesla's go-to-market has always been to start with upscale models and roll out the cheaper stuff later, but Tesla needs to sell hundreds of thousands of Model 3s to make the business work, and as Lutz has noted, the market in the US for $60,000 cars isn't big enough to support Musk's deliveries goals.
Thus, Tesla must have customers who will buy the cheaper Model 3. But Tesla is making them wait and wait. If they doubt that Tesla will ever deliver their car, they could bail en masse and then it's curtains for Elon.