As you say battery breakthrough stories are a dime a dozen (a bit like solar cell breakthrough stories -- I'm still waiting for the $1/watt printed solar cells we were promised in a breathless article on Slashdot about eight years ago). Reality is what you can buy off the shelf now, the ticket price, the lifespan in terms of cycles or years in place, disposal costs at end-of-life etc. etc. Glossy brochures are not the same.
Current off-the-shelf static battery tech like NGK's sodium-sulfur units cost about $2 million per MWh, not $200,000 per MWh but they are expected to last for decades. If they ever solve the little "bursting into flames" problem they've been plagued with they might fit a niche as they're a lot smaller than an equivalent flywheel or other storage system for the same capacity. A drop in price to 1/100 of the NGK batteries is probably going to take a while though.
The Dinorwig pumped storage station in Wales (about 8GWh capacity) cost about $1.5 billion to build but it's been operational for forty years now and will probably last another forty years with a maintenance bill of a few hundred million bucks total. A static battery built of Li-ion cells could match the capacity and performance of Dinorwig at much less capital cost but the half-billion bucks worth of cells would need replacing every five years or so.