Just last week, Tesla lowered the prices of its models by $2,000 in order to partially offset the expiration for half of the $7,500 federal tax credit. Tesla is often known for changing its pricing and model lineup frequently as market demands, so it is difficult to keep the company's portfolio memorized at any given time.

Tesla previously killed off base models like the Model S 60 and 60 D, which were made irrelevant by the 75D models. Now, company CEO Elon Musk has announced on Twitter that the 75 kWh versions of the Model S and Model X will be discontinued.

Musk's tweet said, "Starting on Monday, Tesla will no longer be taking orders for the 75 kWh version of the Model S & X. If you'd like that version, please order by Sunday night at Tesla.com," with Monday referring to January 13, 2019. This is a big deal because the next-cheapest versions of the Model S and X are far more expensive than the 75 kWh models. The Model S 100D with dual-motors and a 100 kWh battery costs $94,000, $18,000 more than the 75D. The Model X is even pricer at $97,000, $15,000 more than the 75D.

We aren't sure why Tesla has decided to phase out the 75D models. Perhaps most Model S and X buyers are already opting for the longer range 100D models. Tesla may be plotting a name change for these two cars to align with the Model 3, which comes with more understandable mid-range and long-range trims rather than trims named on the battery size.

Another reason for the 75D's death may be the popularity of the Model 3 Performance. Although the Model 3 is smaller than the Model S, the Performance version offers 50 more miles of range, a one second quicker 0-60 mph time, and a $14,000 lower price tag.