A rock rolling down a hill is still a wheel.
Spears, straw huts....whatever...man can be lazy or hard working and creative. It's all about needs and desires.
True enough. There have been plenty of setbacks for mankind along the way. Its interesting to consider where mankind would be without the burning of Alexandria, the dark ages and black death etc.
On the other hand, the dark ages seemed to have sparked something and technology exploded out of it.