TBH, I inherently don't disagree with you. I thought it was pretty dumb to sell a car in Ohio on summers and not all-seasons, especially in winter months.
Tesla is constrained by two things on this issue. One, the tires available in the speed ratings required. Keep in mind the current all-seasons on the LR are not speed rated for Plaid, a quite obvious liability issue for the inevitable tire blowout lawsuits. In fact, they just went from a W rated tire to a lower V rated tire, probably to squeeze out a little more range. But with some purchasing and engineering resources, they could get a manufacturer to provide the tires and overcome this.
Two, and probably the more significant issue, is adding more SKU's to their inventory channel for this purpose. The combinations of the options of 2 models, 5 exterior colors, 3 interior colors, 2 wheel options, and 2 steering options means they have 120 possible Model S SKUs in their channel inventory of relatively expensive cars. To add an All-Season or Winter Tire option for the Plaid models adds 60 SKUs to a model line that has been selling at around 10K-12K units a year. You could say "just build it to order" but customers won't like true build-to-order timing, and no matter what you will have to deal with cancelled orders, priority changes, the wrong car with the wrong options at the wrong place in the wrong time. People and dollars would be required to deal with it.
Could it be done? Sure, it can be done. Is it worth it to do? Tesla's assessment appears to be no. We may not like it, but hard to say it's not a logical assessment.