The entire purpose of the Senate was not balance the power of the House, it was to provide states with representation in the federal government. To such end, in the original constitution state governments chose senators -- because the senators represented the individual states -- not the people of those states.

Then the 17th Amendment changed all that and made senators elected by popular votes just like the house members. This, IMO, eliminated the primary reason for having a Senate at all (to represent states). It now simply (poorly) duplicates the same purpose of the House (to represent the people).