There are a lot of practical issues with sending a very young child to public school as well, such as Kashrus. But the main issue as many have said is that Jewish education is not about simply learning Torah with a tutor — it is an entire experience. The messages sent throughout the day in a Yeshiva are that our lives revolve around Torah and doing what Hashem wants, and preschool is the best place to introduce these lasting ideas. When a five year old learns parshat hashavuah and they make projects about Avraham Avinu’s hachnosos orchim, or Rivka Immeinu’s chessed, it becomes a part of them.
Additionally the social issue is a big one. You are put in a situation where either your child’s closest friends will be the goyim she spends her day with, or she must always feel like an outsider. Neither choice sounds like a good one in terms of giving your child a strong Jewish identity and pride. Additionally, half of the “education” our kids receive in school is from their peers, and as much as the krumkeit of the outside world is unfortunately seeping into our schools as well, there is no comparison even to public schools in “good” neighborhoods as far as what the kids are exposed to. I worked for many years in the NYC public school system in a very good district, and never failed to be shocked at what I heard.
miritcha — as someone already posted, if it is really a financial decision, let them contact Oorah.
cleverjewishpun — For the record I wouldn’t leave my kids with a not frum babysitter with non-Jewish kids on a regular basis either, so the argument that “it’s just babysitting” doesn’t change anything for me. The environment and messages a child receives when they’re young make a big difference.
charliehall — Maybe this family should home school their child completely, instead of just for Jewish studies. That would be a cheaper option that allows the mother to be home with her kids without risking putting young children into an environment that does not support Jewish values.