This year S/X production dropped not because there's lack of demand but because of a design / manufacturing refresh.

Here's the story in numbers:

  Q4 2020: 16,097 
  Q1 2021:      0
  Q2 2021:  2,340
  Q3 2021:  8,941
  Q4 2021: 13,109

As you can see, the refresh required Tesla to redo production lines, which were shutdown for the whole of Q1 2021

After that the production is steadily climbing up and is on a clear trajectory to surpass before-refresh numbers.

S/X are sold out months in advance and Tesla reduced number of variants and options, both facts pointing to being limited by production not demand for the cars.

The Model 3 was designed later than the original S and X, meaning it had a fit-and-finish which S and X lacked, at least until the recent refresh. I see that disparity as an example of Tesla disrupting itself, being willing to launch a lower-priced model which could compete with it's own luxury vehicles.

Since then, the S has been refreshed (including Plaid mode), making it more competitive. They are now in a situation where demand outstrips supply, with extensive delays to get hold of a Model X in particular. To me this signals that demand is now there, but Tesla is actively making the choice to focus on the 3 and Y production volume (which also contributes to the Cyber Truck, Roadster, and Semi all not being available yet).

Well they refreshed S and X. To do that they had to completely shut down production lines and sold 0 cars in first quarter. The demand is strong and at some point I tried ordering a non plaid X and the delivery estimates were almost an year out. That’s mostly because there’s a pent up demand that they need to fulfill for the plaid versions before they decide to sell the regular one.

They effectively had a long production outage for those models when they upgraded to the most recent version, with the steering yoke. Wait times were on the order of 6-12 months.