Since 2020, Merc HPP has been designing engines that can run at higher temperature, which in turn help reduce the needs for cooling radiator, I believe this may be the reason for Merc zero sidepod design as it hope that the PU, together with its ability to run a tighter package, will give the team an advaantage which other teams will not be able to copy due to rule on engine development.
For a team like Merc, I am sure sizable budgets, resources and wind tunnel time must have been dedicated towards making the zero-side pod design work, which unfortunately did not yield the desire outcome.
Copying RBR aero design should offer similar performance gain as Mclaren and AM, but the gain may be limited by PU efficiency as it was designed for different type of aero package. Supposed if Honda PU has got some HP advantage over Merc PU, when aero efficiency between teams converges, RBR, with its Honda PU, will still hold some advantage.
In my view, RBR budget + AN aero knowlefge + Honda PU + Max will most likely dominate F1 for some years to come and by mid-2024, if Merc is still unable to close the gap on RBR, I reckon the team may throw in the towel and switch their focus on 2026 car instead of 2025.
"We've also benefitted from an investment that HPP have made on our behalf. They've worked to raise the operating temperature of the engine which eases the cooling burden on us because the hotter the fluid, the less radiator you need to cool it."
https://www.motorsport.com/f1/news/merc ... e/4685459/
