Hence the technically impossible

Theoretically it's possible, just keep removing human problems until it becomes possible, remove religion, remove social class unhappiness, remove starvation, remove financial burdens and so on until everybody is happy, this isn't impossible if humanity either all got on the same page or a great war wipes out a huge amount of the population, it's just never going to happen

In theory it's possible because it's entirely based around human element that humans if they so choose can deal with

In reality its just not going to happen, even if you could solve a few of the problems there will always be somebody around to ruin it, humans just aren't capable of all coming into agreement