Even if this is a necessary condition for a perfect voting system, it doesn't change the underlying problem. Even if everyone voted, you wouldn't consider it a system that "truly reflected the will of the people" unless that voting system satisfied a few basic principles, like you can vote for anyone you want, there's no dictator, only information on the ballots is taken into account, etc. But those principles are Arrow's, and Arrow shows that there can't be a voting system that satisfies them. So there can't be a perfect system at all. What's the point then in making everyone vote?

you can't reflect the will of the people with representative democracy. People have different value judgement, therefor it is impossible to create laws that are 100% reflective of the people.

Democratic representatives do not represent you like a lawyer or financial advisor. They have to act in your and your interest alone, or they breach ethics and possibly get sued. 1:1 vs. Many:1 relationship.