> The emissions weren't so pleasant, however!

Do you mean from cars or horses? If the former, early automobiles were far cleaner than the animals they replaced (and still are). Cities faced huge issues with animal excrement and cars represented a cleaner alternative.

Obviously you can't do such a simplistic direct comparison between horse emissions and car emissions. How does leaded petrol play into this comparison, particulates, etc.

You're totally right, my comment was far too simplistic. However it captures the feelings at the time, cars at that time were far "cleaner" in that they smelled a lot better, did not clog streets with excrement etc

Obviously play the car out a few decades and the emissions were _not_ so clean.

But you do get self replication. Try wrapping your head around that feature.

By the time any consumer product offers self replication as a feature, would anyone even remember what smartphones were?

Have people not seen any sci fi with self replicating mechanicals? It never goes well. Humans wouldn't be around for very long to remember anything at all.

There will always be room for some horses.