Humans invented horse-drawn carriages during prehistoric times, and automobiles didn't fully replace them until the 1930s. But we went from Wright Brothers' first flight in 1903 to putting a man on the Moon in 66 years. Whatever concerns there were in 1840 are a hundred-fold more relevant now.
The reason we even needed a combine harvester is because of the invention of the Haber process. The Haber process is often cited as the single biggest contributor to the human population explosion. We can produce more food than ever before and do it so efficiently that we need fewer and fewer people to do the work.