If you're just talking about the mass involved, I agree....
However, creating a specialized system with the same part replicated a million times isn't the same as constructing a fleet of much more complex Rama-esque L5 colonys.
The control system would be tricky to say the least. Directing traffic in a time dependent gravitational potential for a million body problems with limited thrusting. I don't even know if it's possible without collisions. To say nothing of natural hazards. Then how fast does Venus cool...? If it's millions of years, why bother?
