It is possible to put together automated missions at-scale. But not likely. Because auditors can trim back an automated mission's scope smoothly, no matter how expansive it is, in order to save money. A slightly lighter, cheaper camera, gives way to an even more slightly lighter, cheaper camera, ad infinitum. A hundred units give way to 99 units give way to 30 units give way to 1 unit. But if you try to do that with a manned mission, you start to jeopardize the public heroes you have sensationalized in order to fund the mission. You don't get to send half a human being to Mars.
All manned missions arguments I have seen are somewhat coy in this respect. Yes, geologist can make better choices on spot and take better samples than current drones, but that's not real comparison.
We should compare alternative strategies using opportunity cost.
The money used for manned mission could be used for massive fleet of of drones, satellites and technical development. Missions could be more incremental and cover more areas. Self driving cars are just taking off on earth. How does advance fleet of Mars robocars and satellites mapping Mars compare to manned mission?