For reference: the current Intel-based Mac mini starts at $799 while the iPhone SE (A13) starts at $399.
I think the most standout price for Macs was the original Mac Mini, which was just $500. That was mostly an effort to get Windows users to switch platforms.
In short, I don't think Apple Silicon machines are going to result in a lower price. I think the higher price tags are part of Apple's culture at this point.
So they need something that distinguishes from current range as body style does for SE vs iPhone 11.
Lower prices, why? Apple wants their Mac line to have higher profit margins like their more successful products.
Apple may well have a wider lineup like a MacBook SE but then you're getting less.