Some people really do spend the $ without knowing a definite roster spot. It's called over recruiting and it's done at the college level too.
Those folks though probably value the education the kid is getting and view hockey as a bonus or maybe an equal reason to go to the school. If you're picking a school entirely on hockey.. well you get what you deserve. Things change, kids get hurt, don't grow, don't get better, don't get along with the coach, etc.. million reasons why hockey might not work at prep. But if you pick the school on academic fit first, you're much better off. Same for college..
It also depends on the school. For example, back in the day, the ISL formed two divisions to level the ice, Keller for schools that recruited athletes, and Eberhart for schools that relied mostly on student athletes. The lines have blurred since then, but a school like Middlesex (ISL) or Philips Andover (not ISL) isn't going to recruit a player for every spot on the team.
And, not all kids are Varsity level at 14. My kid played outside his school for his first two years and Varsity his last two years. He "made" the team in tryouts Junior year, but really "made" it by continuing to work hard on development to achieve his goal.