This is a great example of the insane threat scale swings Randy can have at high wealth.
I have nearly 900k wealth but this infestation is a total of 6 hives.
This happens because Randy picks a random multiplier between 0.5 and 1.5 to apply to events like this, meaning despite the clownish amount of wealth I can still have a raid or infestation massively reduced in scale simply because of a really low roll on the raid multiplier.
It wasn't too long ago my tanks were facing down like 30 centipedes in one raid.