Even at the presidential level, we've had incredibly close elections recently. And there's nothing intrinsically preventing the election coming down to one vote.
In any case, like any collective action, the proper framing is the group benefit not the value of a single actor.
And if you are outside the battleground states, there are key state and local elections and major ballot referendums at stake this cycle. Including on abortion rights and drug legalization. These races can easily come down to a single vote. We had a number of extremely close elections during the Midterms that were the difference in legislative majorities.
And it is such a low cost activity.