Model ≡ is about 20% smaller and so about 20% cheaper? Wouldn't that be a reasonable price?
(20% smaller is just saving 20% on raw material costs, right? So cutting 20% from overhead and labor costs is treating us buyers well, isn't it?)
I would not expect Elon to cheapen materials, he always wants to build the best, safest, not slow car that he can. Autonomous system requires all the same hardware and software so cost to buyers could reasonably be the same.
How can Elon maintain profits? If his company can increase productivity/assemble he might well get extra savings vs Model S/X, and the decrease in battery cell/pack costs.
20% savings might be reasonable.
33% savings might be the best we can expect.
Any more than that would be hoping volume helps to spread out the fixed costs (engineering, overhead) and Tesla passes along some of these potential savings.