This would have been a better argument a decade or two ago, but as Republican voters have become poorer and more rural, and Democrat less, a tax on driving starts to hurt just the people who won't vote for them anyway. I mean, I'd still make the argument, but it is less potent than when Democrat voters were farmers and blue collars.
Overall, yes, those are the prevailing trends, but it's not like there is a complete absence of Dem voters living in quasi-urban areas or the suburbs where public transport options largely don't exist. Doesn't matter, anyways; Uniparty Republicans can't make an effective argument for water being wet or the sky being blue (but they sure can vote for another couple trillion dollars in deficit spending!).