I think the switch to un-manned air-craft will come but will occur to different mission sets at different times changing the battle space in ways that are not being considered.It is my opinion that in the incoming years survivability of aircraft will be the issue. Anti-aircraft warfare are right now challenging aircraft defense, deception and e-masking. Aircraft will benefit from the deletion of the crew: smaller size, fewer systems, higher sustained performance, slimmer lines to gain advantage over anti-aircraft systems and enhance survivability.
One final remark: a massive loss of UCAVs would be a sharp pain to the budget, but still tolerable, a massive loss of crews would be a intolerable to western countries.
The first set of missions to be adopted will be deep strike. In many ways they will become like reusable cruse missiles. And the last mission will be that of close air support for close engaged ground troops in a convention war setting. The more a mission can be pre-planned the sooner that mission profile will find an unmanned solution. The more lives that are at stake if a mistake is made the less likely it will be adopted until it is rock solid proven to work.
In the future the major difference in the air order of battle will be seen in reversing the recent trend from building just a few very expensive and complicated aircraft for general mission requirements. Requirements that are written so as that the aircraft can do everything. Which makes them so expensive because they have to be so complicated to be able to do everything, everywhere at any time, at least to some degree and going back to the older order of battle with had required far more specialized air craft for specific missions? Aircraft that will be smaller and cheaper and well as unmanned and made in greater numbers.