Then how do you know they only have a 5% chance of getting into the school that they want to attend? There are around 10 universities in the country with an acceptance rate that low.
Sure, there are many schools that are extremely competitive, but I think you are being a little harsh with your good and great grades. Michigan is a fantastic school with a rabid alumni network and has an 18% acceptance rate. Cal is a great school with a 12% acceptance rate. Florida is a very good school with a 23% acceptance rate. And those are just some of the very good publics.
The difficult reality is that the attributes you identify in your kids aren't all that uncommon in today's college applicants. According to some studies,
nearly 50% of them graduate high school with all A's. I do alumni interviews for admissions from a school with a low acceptance rate (that I would have no chance of getting into now) and every kid I meet is an A student with tons of extracurriculars, fantastic volunteer work, and a terrific demeanor. Most don't get accepted. That's not a problem with the system. That's a result of us as a society producing a generation of high achieving kids who we (as a society) sell the idea that they have to attend one of those sub 5% schools to have a great life.
There are TONS of great options for kids after high school that fit their interests and ambitions. I wouldn't sweat what college they are going to end up at too much. I'd spend more time helping them find their interests and ambitions. If they have those, they can build a fantastic life with their college choice being a small part of that. If they don't have those, no college choice is going to magically help them find those.
Sorry for the wild detour, but this is a topic I'm passionate about so I hope you'll forgive my rant.