Not necessarily true in Tesla's first MX market, though. US safety regulations tend to be way stricter than those found in Europe. I can't buy, import, or legally drive a Twizzy in NA also due to safety regulations, and the Twizzy is the only way to get an electric car that's as cheap as a regular ICE vehicle.
I should have clarified that it was in the US market. There almost certainly has to be some sort of engineering challenge in fitting all of the following in one vehicle: seat-attached seatbelts, a 5-star safety rating around the board, Falcon wing doors, independently moving seats, single-pedestal seats, and folding seats all in one vehicle. Something had to be dropped to accomplish all of the above. The falcon wing doors and 5-star safety ratings are un-droppable for Tesla for the MX. There are good reasons (storage space, independent movement) to keep the single pedestal on the vehicle.
Tesla isn't stupid, as of today Tesla has no feasible way to design all of the above, so rather than drop the uniquely-Tesla features, they decided to drop a feature you can find on every other vehicle. That's that. If it breaks your deal, you're more than welcome to go with the hundreds of other models with folding second row seats. You won't get any of the unique MX features because, with current engineering challenges, it very much looks like you cannot make second row folding seats while simultaneously keeping the MX as a MX.
Not to mention features like cooled/ventilated second row seats, and second row seat quality.
You don't get Tesla grins from folding seats, you get it from industry-breaking falcon-winged doors and independently moving seats. I'm sure Tesla will someday have folding second row seats, either as a dumbed-down bench seat or through engineering advances, but they don't want the first impression of their most luxurious and adventurous vehicle to date fall short on said adventurous promises.
The MX is probably the only vehicle I can think of that has kept crazy concept-car features into production, and other automakers are going to take notice.