I've previously done a simple calc to estimate potential market cap by taking quarterly revenue and dividing it by quarterly vehicle production to figure revenue per vehicle.
For this year the revenue per vehicle averages out to approximately $57,737.
Annualized to 3 million vehicles produced, revenue would be $173B and using a price to sales ratio ranging from 18 to 30 we could see market capitalization of $3.1T - $5.1T. That's a share price of $3,149-$5,248.
Arbitrarily reducing revenue per vehicle by $20k to $37,737 to account for a high volume cheaper model Tesla leads us to the following estimates:
Annual revenue: $113B
Market cap: $2T to $3.1T
Share price: $2,058 - $3,430
The price to sales ratio of 30 and 18 were both hit this year which is why I used them. However over time growth will slow and the P/S ratio should decline eventually to the high single digits.
Using revenue per vehicle is quick and dirty math to come to a ballpark estimate. By the time we hit 3M in vehicle production the revenue per vehicle will be affected by vehicle mix including plaid s and x, semi, roadster, cybertruck, and low cost model.
Price to sales ratio could stay in the double digits for some time if the market agrees Tesla will continue to see 50% or higher production over the next decade, but at some point its probable we will see a lower price to sales ratio as seen with the likes of AAPL (7), FB (10), and MSFT (13).
I like to use my estimates as reference points. As new data comes in I can make adjustments, but it gives me a rough idea of what to look for.
Hope it's useful