>> It argues that the hybrid pack (minus the battery, perhaps?) is more compact and simpler than a manual gearbox, even.

Having worked in the field I've been of that opinion for 15 years or more. Two motors and a planetary gear are simpler than a regular transmission. More efficient also, and more reliable. The inverter and small battery may add some cost, but the MPG improvement is more than worth it.

Hybrids are an awesome improvement over plain old ICE, but they tend to get an unnecessary price premium due to their advantages.