It is always necessary to make some choices and sacrifices to operate communal institutions. I think it's far more important to cultivate a Jewish home life than to make sure your kids only hang out with Jews at school. In my family, kids went to day school for at most elementary school. We now range from 17 to 25 years old, and all five of us are still Jewishly active. By the way, I think we spent at most 5 or 6 years at Jewish summer camps among us.
Regular practices can also be expensive.
This just isn't true. Of course, this won't get you top of the line stuff, but it's perfectly respectable. Kosher food is indeed more expensive, but it depends on your level of observance. If you merely avoid non-kosher foods but don't get glatt kosher meat, there is little or no additional cost. Claiming religious holidays, too, is kind of unfair.