I know an efficient steam engine was necessary for the Industrial Revolution c1780, but was it sufficient? Or, if other social factors were necessary, were they present earlier?
So, if Thomas Newcomen invented the Watts engine instead of the one he did in OTL, would the Industrial Revolution have occurred c1720 and we would now have bases on the Moon and Mars and surf the web by direct neural input, or would the better engine have just been a marginal feature of society for half a century until the IR took off?