I don't know about the Model X, but for the Model S, let's be honest, it's an industry trend.
Try to buy a big, expensive 4 door luxury sedan from the brands that used to be synonymous with those cars: Cadillac, Chrysler, Lincoln, or Jaguar. Chrysler is cancelling their 300 for the 2023 model year. Cadillac only has the smaller cars now. Lincoln, of all companies, abandoned cars all together.
Tesla needs to do a complete redesign of the Model S in the next few years. It's not so far fetched to think Tesla would decide to leave the market instead of making that huge investment in an ever-shrinking market.
And EV's don't make for comfortable luxury cars anyway because of the lack of footwells, due to the big batteries. EV's are much better off as SUV's for that reason.
And no, none of those extinct big 4 door sedans became instant collector items. You can buy them dirt cheap today, as would be the case with the Model S.