Not sure why you're thinking that. If you go to the reservation page, the base model price is listed at $200K, with a $50k deposit required. And the Founders Edition price is listed at $250K, with full price paid now.
That would be my preferred assumption too.
However, legally, it doesn't say it's any where near to a purchase price. It's only a $250,000 upfront reservation payment.
Historically, a base Model S was first quoted as
$57,400 (or $49,900 after federal tax credits) but when added paint color, navigation, tech package... my general production model became $100,000 which is about doubling the base price.
The same with Model X base price which was expected to be $60,000 to $70,000 but then when you added options, it was quoted as
$132,000 which even elicited a sticker shock from a pro-Tesla Morgan Stanley analyst Adam Jonas.
The same with Model 3 which is quoted as $35,000 but when you add full-self driving and other options, it would also be heading toward the zone of doubling the price (which lacks ludicrous/plaid mode and other mandatory Founders maxed options.)
Base........................$35,000.00
310 mile range battery.......$9,000.00
Optional color...............$1,000.00
Premium Upgrades Package.....$5,000.00
EAP+Full-self Driving........$8,000.00
19" Wheels instead of 18"....$1,500.00
Destination..................$1,000.00
Total.......................$60,500.00
Thus, may be the base price of $200,000 Roadster won't double up to approximately $400,000 with mandatory maxed-out options because this time may be it will be different?