I'm no so sure about that. Since leaving social media, I've become quite involved in local politics. I now know some state legislators on a first-name basis and multiple directors of state departments in multiple states. I can call up people I've helped get elected and get my thoughts right to them. I find my opinion to effect much more change than it did when I was shouting into the digital void.
How about regular citizens who voted for those people but didn't "help them get elected"? Do they get to voice their opinions? Or what you're saying is that your politicians only serve those who directly donated resources (time is a resource) to them? Even though they should theoretically serve their whole constituency?
Like much in life, half the battle is just showing up.
You don't need social media to inform your representative of your opinions--and quite frankly, more direct communication is probably more effective in informing your representative of your opinions than social media.
Oh, irony..