I remember reading something on the JPL's Laboratory for Reliable Software (LaRS) which suggested we were in the hunter gatherer or early metalworking (bronze age vs. composite material design) stages of programming. Agile is like the idea of crop rotation and organised teams of farmers. At some point in the future we will work out something like artificial fertilizers, pesticides and automated systems that would give us hundreds of times the output per-worker with much lower error rates. It took us a few hundred years to get finance as far as it has come today (which is still a bit error prone at times) so it seems reasonable to expect other professions like programming to take a century or two to find their stride.
TLDR; things are getting more productive but they will probably get hugely more productive and not be that recognizable to us as programming any more.