That’s a bit of an assumption, there’s some lore hints that the Warp Storms weakening might have been more deliberate than previously implied.
The idea being Slaanesh’s birth is what made the other Chaos Gods really sit up and take notice of how much free psychic power an evil galactic empire of murder monkeys can generate, so when Useful Idiot McGenocide was ready to start conquering they made it so that he could and cleaned up Slaanesh’s afterbirth as it were.
Of course, it’s 40k, there’s all kinds of lore hints that never get any further explanation.
That’s a bit of an assumption, there’s some lore hints that the Warp Storms weakening might have been more deliberate than previously implied.
The idea being Slaanesh’s birth is what made the other Chaos Gods really sit up and take notice of how much free psychic power an evil galactic empire of murder monkeys can generate, so when Useful Idiot McGenocide was ready to start conquering they made it so that he could and cleaned up Slaanesh’s afterbirth as it were.
Of course, it’s 40k, there’s all kinds of lore hints that never get any further explanation.