I would not entirely agree with that characterization.

Upsizing the entire power delivery system in a laptop to support continuous, unrelenting maximum power drain conditions for an extended duration does not fit with the requirements most laptops are tasked with.

It would require the power adapter to be larger and heavier, which for a portable machine is not a good thing. It could also require larger and higher heat output componentry in the power management system within the laptop. More weight, potentially less efficient overall power usage.

All that just to avoid calling on the battery during typically short duration ‘max computing’ events?

Portable devices always involve trade-offs. Weight, size, heat, battery durability, power consumption. Everything affects everything.