I've often wondered why bicycles weren't invented earlier.
Chariots have been around since 2000 BC, so the technology to create the bicycle has been in existence for almost 4000 years.
In the late 1700's the Industrial Revolution surely provided enough tools to turn 1764's Spinning Jenny into a cycling Jenny.
Then there was the rapid evolution of the car. All the way back in 1769 a French inventor named Nicolas-Joseph Cugnot created a steam-powered car, and in the late 1800's petrol-powered internal combustion engined cars appeared.
The development of the bicycle was much shorter, but much later. The first one that wasn't propelled by running along the ground was a treadle-powered model of 1840. In the 1860's the familiar pedals were added, and by 1900 the essential elements of the modern bike had been born.