It’s not a matter of relying on the ball to grab your attention, it’s being alert to risks, and when you see the ball being aware that it may indicate another risk which isn’t yet visible.
""You don't need to forecast what other vehicles will do," he states boldly."
I'd argue that any competent driver is reading the road, and by extension forecasting what others around them are likely to do. For instance, you're in the middle lane approaching someone in the left lane, and see that they are catching up with a slower vehicle in the left lane. Long before you reach them you should be aware that they will likely want to pull out shortly, so have plenty of time to see if the right lane is clear, and decide if you want to pull into the right lane, or increase/decrease your speed as appropriate. You shouldn't be reaching that car and be surprised when they indicate that they want to pull into the middle lane. Autonomous cars should do no less.
"...predicting what others will do saying it would simply create too much information to effectively compute..."
What I think that means is it's too hard for them to code, so rather than find a way to do it they're going to ignore the problem.