Why are so many people convinced that automation is going to improve productivity to the point that the majority of people will be out of work?

I worked in tech for years and this was a common mindset, and I see a lot of it on this sub. But I don't understand the reasoning behind it. <br> <br>Additionally, it appears to be somewhat contradicted by labor statistics. Even with a large shift in the economy over the last few decades from manufacturing jobs to service jobs, labor participation has remained around 60% for most of the last 50 years. And real wages for most workers have not improved but actually stagnated since the 1970s despite huge gains in productivity. I don't see why that trend will change in the future. Instead of people working more hours, I think they'll just work jobs that are less productive and more fulfilling.