It’s also possible that AI used to be hard but no longer is because something in the universe recently changed. Although this seems extremely unlikely, The Fermi paradox implies that something very unlikely is indeed occurring.
Not that unlikely, depending on what you mean by “recently”; for example, earlier stars had lower metallicity and hence were less likely to have rocky planets.
It’s also possible that AI used to be hard but no longer is because something in the universe recently changed. Although this seems extremely unlikely, The Fermi paradox implies that something very unlikely is indeed occurring.
Not that unlikely, depending on what you mean by “recently”; for example, earlier stars had lower metallicity and hence were less likely to have rocky planets.
Or space colonization is just hard.
The evidence seems to be that it’s “easy” (see http://lesswrong.com/lw/hll/to_reduce_astronomical_waste_take_your_time_then/ ), at least over the thousand-million year range.