While you have some fair points,
in 2017 North America has made up 53% of Tesla S/X sales. Not 25%. I don't think we have regional numbers of Model 3 reservations to be able to make such a claim.
Yeah, thanks for the correction, I was thinking more in terms of expected global demand for the Model 3, which is only sold in US+CA right now. The base price is about half of that of an S/X and addressable markets strongly depend on income distribution and GDP per capita.
If we go by the following annual income distribution of the U.K., overlaid with new car purchase price distribution (2013 data):
Then we can see a remarkably consistent relationship: new car prices roughly track the annual income of the person, with a lower cap at around $10k-$15k USD. (Below which new cars really start to suck.)
2013 UK per capita GDP was around $42k, which corresponds to an about $30k new car price.
From this histogram we can estimate the expansion of Model 3 addressable market if the Average Sales Price drops from $104k Model S/X to the ~$57k of the Model 3: it's a massive expansion of at least a factor of 10. Beyond the lower half of advanced economies this is going to push the Model 3 to emerging markets as well that have lower per capita GDP levels, and is going to shift a lot of demand to non-US markets.
Note how the reduction of the entry price to $35k will put the Model 3 right in the middle of the histogram: its pricing is going to be accessible to about half of the population in an economy like the U.K.
If we also weigh it by revenue (a $60k car sale is equivalent to
three $20k car sales) then it gets even better for Tesla. I am not surprised at all that they cannot seem to be able to run out of demand in the U.S. alone.
If we also weight the histogram by margins then it gets even better: with the Model 3 Tesla will have access to over 75% of all the gross margin available in the automotive market, avoiding the cut-throat low margin high-volume lower segment entirely.
The only missing piece is the Model Y: there are consumers who won't buy sedans, and by adding the Y Tesla rounds up their offerings.
But even with the Model 3 alone the addressable market is huge, and Tesla possibly won't be able to make enough cars for the next 5 years.