Seems a low price for no-click zero-day infections
Doing digital forensics on a restrictive mobile device (like an iphone or decent android phone) is difficult.
> WhatsApp and Signal must know of this, don't they have some AI tools to fuzz and fix?
Sure, but it's not a simple thing. That's why these exploits can go for millions. If it was easy to "fuzz and fix" these exploits would be worth nothing.