There's a bit more to it than that.

Battery production is being invested in heavily. There are new types of batteries (like sodium ion) that are extremely relevant to the article that it barely even mentions. The pitch for those is of course no lithium, better temperature ranges, less need for cooling/heating them, much better fire safety, better durability, etc. This all adds up to lower cost when done at scale. That all adds up to a lot less cost for especially grid storage.

I agree the 33% number is meaningless. It's probably too conservative. The article actually does not talk about new battery chemistries like sodium ion. And given that large scale factories are already producing those by the tens of gwh, I think that's more than a little oversight. Additionally, there are learning effects that explain the large differences in prices between markets that the article mentions. Those are optimizations that countries have yet to implement. Some might not get around to that any time soon (like the US seems a bit of a basket case on cost/efficiency for a lot of things).

Because of the improvements in battery cost relative to the stagnating improvements in gas turbines, gas turbine manufacturers are going to be conservative in investing in new production capacity. A lot of companies that say right now that they are going to want to buy gas turbines might no longer want to in a few years. For example the low cost and ready availability of solar+battery might be persuasive for some. Investing many billions in new production capacity that won't come online until some time next decade is highly risky if the projected demand could evaporate. The reason there is a shortage is that that's what they thought five to ten years ago as well. So, it's easy to predict that turbine shortages might continue to exist.