Anti-saturation tactic must be cost effective. In other words, the means you use to shoot down the incoming saturation attach must be cheaper than the saturation attack.

The patriot missile defense system is a case in point. Taiwan tried to buy more, but the simple fact is that the Chinese attach missiles are a lot cheaper than these anti-missiles and the anti-missiles are not 100% effective. So the Chinese just need to match these batteries, missile for missile.