The overall profit margin could be higher. Imagine Tesla makes $10K from autonomous software (FSD + RoboTaxi service) per car (I am making this number up).
$10K on a $45K model Y, vs $10K on a $25K model 2, guess which one has higher margin?
This is why, if Tesla can succeed in its autonomous and robotics vision, its valuation could be significantly higher. If Tesla is only a car company, its stock is probably $50 max.
Anyone who holds Tesla stock for long term is betting on that future.