The Rivian R2 is not $20k more. It’s $5k more than the deeply stripped down Model Y base model.
The R2 base model is not as premium as the higher models but the Model Y base model is really deeply stripped down including some really barebones stuff like removing liner material from the frunk and removing some of the exterior LED lights.
Cheapest Model Y is $40k and cheapest R2 is $58k. Cheapest Model 3 is $37k. The vast majority of Teslas sold are in an entirely different market than Rivian, which hasn’t even started delivering R2s yet.
So really, the price gap is $40k or more until R2s are actually delivered.