The United States Federal Government was obstinately set up to minimize the aforementioned trend, but several big mistakes (Reynolds v. Sims and the 17th Amendment top the list) along the way and 200 years of mission creep have undermined most of the protections put in place.
You're claiming that Reynolds v. Sims was a bad decision? Without it, you could have stunning levels of effective disenfranchisement; all the party in power would need to do is to allocate all the strongholds of their opponents to as few seats as they could get away with (preferably one!) and split the remaining ones among the areas that they dominate, rapidly leading to an effective, perpetual one party state with no hope of ever changing it.
Any functioning representative democracy has to have something similar in place to limit the levels of unfairness. It might not stop shenanigans, but it limits things quite a lot. If you want to argue against it, please explain on what grounds you believe it to be a problem, and why what you would replace it with would not be worse.