Starship becomes “fully and rapidly reusable”, needing little to no refurbishment between launches. Then the lower bound of launch costs is just the expendables (methane, oxygen, nitrogen) which could cost as little as $1M per launch.
SpaceX uses custom silicon (produced by “TeraFab”) that can run at higher temperatures then the radiative cooling requirements goes down significantly and a 100 kW satellite might weight around 1 ton.
Starship should be able to launch at least 100T payload. Assuming they could fit that many, that puts the launch cost per 100 kW at $10,000, which is a rounding error compared to the cost of the chips alone, even if it’s off by a factor of 10.
Obviously a lot needs to go right for this to happen, but it’s not impossible.