To be sure, I'm not saying cars weren't an improvement over horses (history proves they obviously were), I'm just saying that after a century of car culture we're probably somewhat inured to and/or have engineered around the negatives of car ownership, so they've become invisible to us. Now it just seems like a near-perfect drop-in replacement, which I guarantee it wasn't at the time.

That said, I'm unconvinced that smell and mess are as compelling a selling-point as all that. Societally they're very important, but not obviously more than non-fuel-burning vehicles today. In practice, when it comes to making a purchase, there are often much more pressing concerns than an environmental issue over which you individually have little influence.