arbitrarily large means like measured in square km. Starcloud is talking about 4km x 4km area of solar panels and radiative cooling. (https://blogs.nvidia.com/blog/starcloud/)

Building this is definitely not trivial and not easy to make arbitrarily large.

When a physicist says arbitrarily large it could even be in a dimensionless sense. It doesn't matter how small or large the solar panel is:

for a 4 m x 4 m solar panel, the height of the pyramid would have to be 12 m to attain ~ 300 K on the radiator panels. Thats also the cold side for your compute.

for a 4 km x 4 km solar panel the height of the pyramid would be 12 km.

A size like that is going to be completely, absolutely obliterated by micrometeor collisions.

These people are all smoking crack.