First, the studies mentioned in the piece (you have to go into the comments to find them) are all about English as a second language. They have no relevance as to whether or not grammar instruction is valuable to native speakers (who already know English grammar before they reach school-age and where such instruction is largely in terminology). Walter, the author of the piece, very disingenuously avoids making this point explicit.
I haven’t gone through the studies, but several of the commenters have and, according to them, they do not support the notion that grammar instruction is essential, not to the degree that Walter is claiming.
Third, Walter is the co-creator of an ESL grammar course. So she’s got a financial stake in promoting the concept.
So this says absolutely nothing about the value of teaching grammar to native speakers and is inconclusive about its value to ESL students. It’s another poorly written newspaper piece that adds nothing of substance to the debate.