Go ahead. Invent some new tech that absolutely no one know about or how to do and that isn't based on any known tech. I'm waiting. What's taking so long?
Discovering stuff is hard and harder if you don't think you need it. People kept fire going before they knew how to start fires. If you don't know about the concept of flint or lighting dry stuff with sparks, it is really hard to invent fire starting. Writing isn't as useful if you can just learn what you need to know while growing up. A more complicated world later - as are discoveries slowly started to build up - probably created the need.
But again, those discoveries are hard and they took time. A really long time, apparently.
I think there is a tendency to project the modern era's speed of technological progress back in time, which isn't reasonable. We went from the Wright Brothers to Apollo 11 in 66 years. The first transistor to the iPhone in ~60 years. That rate of development is...new.
Some people think it's fine for the process to have low precision but high recall. Low precision is that of the number of conversations the process flagged as a positive, some unacceptable (to you) percentage turned out to be a not/false "positive". High recall is that of all the actually positive conversations, the process flagged an acceptable (to you) percentage of them as positive (i.e. only "missed" a few/false negative).
What does it cost to wrongly identify conversation a positive when it's really not a positive (false positive)?
What does it cost to wrongly identify a conversation as a negative when it's really a positive (false negative)?
You decide.