1. I think you will see the human interaction taken out of the atc system first, with automated control of routing/altitudes directly from a ground based computerized system that can talk to and control the aircraft's autopilot. While technically possible today, even that I would put in the 15-20 year range.
2. Many of us have done this single-pilot. It's not that hard, but it is fatiguing. If you take a pilot out, you likely have to decrease pilot utilization to decrease risk, therefore no real cost savings. Cost or mandated safety are the two big drivers of change, so I don't see a big push from anyone to go single pilot in the next 20 years.
3. Eventually we're going to get to the point of automated scramjets flying LA to London in an hour. Or Elan Musk is going to build 600 mph underground mag lev trains that connect everywhere domestically. There will be a next generation that makes air travel as we know it obsolete. It's inevitable. No one riding a horse in 1890 thought the car would take over. However, big leaps in aviation tend to come from the military first. Without WW1, the fledgling aviation industry probably stays as a fringe hobby for another decade or two. WW2 brought us jets. The Cold War space travel. GPS, drones, etc. The amount of capital to bring revolutionary change to the 121 world is mostly beyond what any one company can effect. I put you at 50 years out from an automated aviation industry (which may not be even "flying" as we know it anymore).