Still, an announcement from a big company like this is a lot more credible than from research labs or small start-ups, IMO.
However the prices seem to have come down a bit despite all the inflation since then.
Their main energy density boost is a silicone anode, which we've known "for ages" that it leads to higher energy density, but soaking it with lithium degrades the material very quickly, leading to cracks and thus damage after just a few charge cycles. The main innovation is some kind of nano-structuring of the anode, and that technique was published in the scientific literature in 2006.
I'm sure it was hyped as a battery break-through in 2006, and it has taken 17 years to get to market.
So, maybe we shouldn't go back 5 years, more like 20 years (OK, no HN back then :D).
Batteries do get better over time, fairly consistently so. The development lifecycle is just soooo much longer than in software.