The linked editorial doesn’t say “a necessity”–it says “a valuable component”. There’s a difference.
I don’t think anyone would disagree that preschool is a “valuable component” of education.
Second, the point of the editorial is not “whether pre-K is necessary”. The point of the editorial is “who should pay for the Pre-K program at Delmar Elementary School–Delaware or Maryland?” Just pointing that out…
I have never heard any reputable mainstream educators state that pre-K is a scientifically proven, research-validated, test-score-boosting “necessity”.
My personal experience is that I never had preschool, and I turned out okay. Back when I was in kindergarten in 1960, kindergarten was basically playtime, so you basically spent your kindergarten year learning about socialization and your ABCs. First Grade was where you started reading and writing.
But.
By the time my three kids hit the Decatur school system starting in 1989, the school system had turned up the amps on the educational process, and they had the kids hit the ground running from Day One learning reading and writing in kindergarten. The kindergarten teacher had the kids copying sentences off the blackboard into journals by Christmas. Kids don’t have a year to spend learning their socialization and ABCs in kindergarten anymore, so if your kid arrives for kindergarten not already knowing those, he’ll be left behind, badly.
Actually, most schools hold kindergarten screenings in the spring for the following fall, and if your kid needs work on something like using scissors or number recognition, they’ll give you a schedule to follow for the summer.
So as to whether it’s a “necessity”, the answer is “yes, given the current academic climate”. When your kid’s college sends your incoming-freshman kid a flyer saying “These are the things we’ve found that freshman in the dorms find helpful to bring”, and you ask, “Are these things really necessary?”, well, it depends on how you look at it. If you don’t want your kid to be the only kid on his floor unable to make his own popcorn, you get him a teeny microwave. And if you don’t want your kid to be the only kid in kindergarten who can’t cut with scissors or who doesn’t know what to do when the kid next to him won’t share the glue, you teach him.