Is it really? I always though the main financial difference between going for (1) a good school district or a (2) private school is the residual value of the investment. At the end of the 15 or so period, you have built equity in a property for the latter, but not the former. Now if the private school is cheap enough you might end up with the equity in your pocket. There are other considerations of course, such has the safety of your neighborhood, neighbor's kids, etc.
private high school in the bay area is about $15k/kid/year.
cupertino has one of the better school districts. sunnyvale is right next door to cupertino and is not renowned for their school district like cupertino is.
the median price for a house in cupertino is $1.3M.
the median price of a house in sunnyvale is $660K.
Both towns have a roughly similar YoY growth [1]
if you assume 30 year fixed mortgage at 3.6% with 10% down for both (assuming good credit and no property tax or pmi, to keep things simple) the mortgage for the median cupertino home is $5,319.35, and the mortgage for the median sunnyvale home is $2,696.50 [2]. That difference is roughly enough to send two kids to private school.
Obviously, that is just a back of the envelope calculation and doesn't compare the price for similarly sized houses, or adjust for taxes, crime, and a bunch of other things.
As for equity, yeah, it's there but unless you plan to downsize, it's not doing that much for you. Having seen the real estate bubble and subsequent crash in Sacramento during the 2000's, I think treating your primary residence as an investment is extremely foolish.
