That's why you also want integration tests
You're correct. Integration Testing is essential. The problem is that the number of combinations of events and conditions quickly becomes too large to test exhaustively. And sometimes sequencing matters. And sometimes not only sequencing, but timing of events matters (e.g. race conditions). Integration testing, while essential, can be a crap-shoot. Many bugs will be caught. But maybe not all of them.
There are other problems. For example, designers are often (usually in my experience) resistant to the notion that their design sucks and that real people can't use it reliably. Their solution tends to be to improve the users -- which oddly enough is often (usually) not well received by the users
... And management often, not always, but often, understands very little of that.
Answers: I don't have any. e.g. Don't count on me to be an early adopter of autonomous vehicles even though I think they are great idea that will eventually make the world a better place.