The time it takes to get from say a car that just drives about randomly to a car that drives pretty well 75% of the time is about a day's worth of work with today's technology. Going from 75-80% is a week or two. 80-85% is months. Getting to the 90% is years, and who knows what we need for 99+%.
I did a self-driving car in GTA V project that streamed on Twitch 24/7. If the car wasn't improving noticeably day by day, people were getting angry and frustrated, as if the car was meant to be perfectly driving within months, surely!
There's definitely a major disconnect between the hype and reality of what the challenge of self-driving cars is. The bubble is just simply bursting at the moment, but the dream itself is not dying amongst actual engineers. It's just dying for the people who never understood how absolutely challenging the problem actually is.