WhatsApp stops you from getting caught in dragnets and requires someone to explicitly target you, with an actual cost for the attacker - when the malicious app

WhatsApp stops you from getting caught in dragnets and requires someone to explicitly target you, with an actual cost for the attacker - when the malicious app is detected, the vulnerabilities it uses will be patched, requiring new ones to be found or bought. The more people targeted, the greater the odds of detection. So, while every single person is pretty much as vulnerable as ever, as a population this is still a big improvement.