The political system in the US biases area over population. The Senate will remain conservative as long as rural states remain conservative, and that will never change.
I'm not sure I'd bet on that. Cities are almost universally liberal, and even rural states start to turn blue as they get their own big cities.
Unfortunately without proportional voting being mandated purple states like Texas remain solidly red due to vast gerrymandering purposefully made to deny people the right to their representation by diluting their vote. This is actually the main cause of polarization in the US as candidates need to play to their base instead of moderating to play to a moderate base.