My suspicion is that this is partially risk based pricing for Motorola. They know some people value privacy, but they aren't banking on lots. So if they're putting the work in on this they want to see the value back.

Well, their requirements increased since Pixels got arm memory tagging in the 8 generation. The 11 would be more secure than a 7 for example but they are still uncertain about supporting them, because it is a clear security downgrade

Pixel 6 isn't cheap.