Tesla is in a special type of market scenario:
- Tesla is cannibalizing ICE markets - which are mostly commodity markets were ICE cars are easy substitutes for each other, even in the luxury segment.
- But you will not be able to cite a single example of an ICE car model that is attracting former Tesla buyers in any meaningful percentage.
- Tesla customer retention rates are very high - pretty much the main scenario when Tesla owners go back to ICE cars is when their circumstances change and they aren't able to afford to have a Tesla anymore.
Which results in a one-way cannibalization of ICE sales by Tesla and in this kind of growth:
Of course, the regular economics of products without substitutes applied to Apple's iPhone for about 10 years, and it applies to Tesla cars as well.
The overwhelming majority of ICE cars are not such products though (they are commodity products), which is where your confusion originates from.