The setup of the Senate where every state has two Senators was intended to protect smaller states against larger states. At that time each state was a lot more autonomous than they are now and it made sense. In 1790, Virginia, the largest state by population had 12 times the population of Delaware, the state with the fewest people.
California now has 66 times the population of Wyoming. Today half the Senate seats are instates with 16% of the population. Far more of these states are reliably Republican states where the few Democratic senators are an endangered species at best. Of the seven least populous states with under a million people, only Delaware and Vermont are blue states.