Your proof is that it would be really bad if everything were horribly insecure therefore it must not be true. Proof by wishful thinking has never been a valid argument.
In contrast, a few years ago I worked with a vulnerability broker who had literally hundreds of unsold zero-days with tens in each major commercial OS with zero-click RCEs only being a few million each. That is just one vendor in a sea of vulnerability brokers. That is the state of reality. We just live in the metaphorical equivalent of the pre-9/11 world where you can easily kill a lot of people by flying a plane into a building, but nobody has figured it out yet.