I think the author is explicitly NOT stating that battery technology has reached it's peak, but rather the safe bet isn't on huge changes in a decade time frame.

He's not commenting on the tech so much as the wisdom of ASSUMING it will be better in a certain time frame.

He's saying, it's not wise to build a business on top of the idea that battery tech will progress predictably or at all.

I disagree, because any business built on that will be the first to exploit it properly when it comes out, as a competitive advantage. But if they're wrong, they'll deal with the downside risk of, you know, being wrong.