It happens when the cost of food, clothing, energy, and housing becomes essentially free, and that happens when there is no longer a labor element in production.
Eventually the only contributors to cost will be human labor by workers and the hoarding of property surplus by owners. When we make the first one disappear by our technology, the entire moral underpinning of the second one will no longer exist, and people will no longer stand for it. The wealthy will no longer "deserve" any more than anyone else when value is being generated by computer programs and robots, and they just happen to accidentally "own" the programs or the robots. This is already true of finance, but people's minds haven't caught up with it yet. It used to make sense that someone deserved to be rich while someone else was starving to death, if they had cleared and plowed and harvested a field, or invented the equipment that better did those jobs. But we are already a long, long way from that kind of "deserving," which is why the 1% so desperately and fraudulently analogizes their privilege back to people who do actual work.
Some day, nobody will do actual work for 99% of the tasks that support our needs. Right now in fact that number is probably already above 50%. At some tipping point people will realize that in a world where everyone is doing nothing but what is enjoyable to them, whether that is art for the very smartest, or science for the middling smart, or drinking and screwing for the dummies, then everyone is equally entitled to the goods generated by technology. That's the inevitable future of technological progress. Wealth is an intermediary stage of economics, like monarchy was in politics.
