My explanation is that some writers in the technical press got taken in by the idea (possibly encouraged by exclusive stories and other favours by the industry) and wrote a series of articles about self-driving cars, how they will change driving for ever, save lives, etc. This started happening a few years ago, around the start of Google's self-driving project.

These writers, being tech writers and not AI experts, didn't understand the subject very well and basicaly just repeated the industry's claims without really understanding the state of the art.

Then people reading those articles who also were not AI experts and didn't have much of a technical background anwyay (except being interested in cars) got taken in, thiking that if the press says that self-driving cars are just around the corner, then they must be just around the corner.

Why did software folks in particular got taken in? Because most people who write software don't write AI software and even many who use it don't understand it. Computer people are used to thinking of computers like magical dream machines, so the common reaction to overinflated claims about AI in general is wonder before surprise and cheering before skepticism.