This is simply untrue. Conservatives have an outsized advantage because of organizing local voting. Most competitive voting areas are decided by thousands of votes, that could easily be decided by non-voters.

Also the majority of Americans do vote.

But items like vote roll purges, not having voting day be a holiday, anti-mail in ballot efforts, general lack of civic education over the years and in the msm have had a much larger effect than simple “indifference “.