I assure you, they do regularly. A123 is the most well known example, but the vast majority of new developments don't involve a new company being formed. Making batteries is hard and few researchers want to build companies. Instead these developments quietly slip into commercial formulations as continuous, incremental improvements.
There's certainly an unending flood of hyped up articles about new experiments, but all of those have some kind of caveat that's glossed over. Cost, manufacturability, or performance. One is always missing. They're usually pop articles or university releases that misunderstand, misquote and play up the papers involved.
This is a release from a private company that hits all three of the important targets. Those are pretty reliable, normally. Flow batteries are an exception, but that's because the professor behind that is way overenthusiastic about them and needs large-scale funding. He's kind of notorious for overpromising; I remember a story by a student under him who used his calculations to derive the scale at which flow batteries became economical and found it was an order of magnitude bigger than a power plant. The professor himself had set up those equations but never actually done them to figure out how big the battery needed to be.
Leydenjar comes off as very conservative in this release. They're announcing an insane improvement, literally decades ahead of when it was expected. Most people would have announced this in coin cells but they waited until they had developed a mass production machine and tested it, and they seem to have replicated those results. Even if this costs 3x more than normal batteries there will be huge demand for it. The battery in an iphone costs $3. Apple wouldn't even blink if a 50% better battery cost $60.
These guys are saying that they pretty much have a product already. Pouch cells make up the majority of batteries that aren't in laptops, teslas or power tools. They've got a manufacturing machine BUILT already and appear to expect a high cycle life. I'm pretty inclined to believe them if they say they can make these affordably.