Do Ivy League schools actually provide for better education or it's just signalling and status?
Both, as well as forced socialization with an impressive peer group. But Lumifer has this one right - both are scarce resources, and this particular mix of the two is a scarce resource, but it's not being burned because it's not a commons. They are successfully accepting only those they think will do well there and improve the environment for each other.
It's a plain old competition, and I've seen no evidence of suboptimality. Are there other highly-competitive endeavors which you think are optimal? You mention Olympic medals - I've known some Olympic hopefuls, but they burned out or were injured before making the team. That's not pleasant, but it's not suboptimal, it's what has to happen in order to identify the best performers.
It's a plain old competition, and I've seen no evidence of suboptimality.
Yep. Basically, the "waste" of competition is the price you pay to acquire information about performance.