1/2 RT @pkedrosky: Horses & mules vs tractors: technology spreads slowly (Source: http://conversableeconomist.blogspot.com/2014/04/when-technology-spreads-slowly.html …) /v @joehas https://twitter.com/pkedrosky/status/457197018864033792/photo/1pic.twitter.com/EGvhH4drhl
3/2 Note that cross-over point is actually decades earlier than graph shows, bc each tractor >> 1 mule @pkedrosky @joehas @ModeledBehavior