The job-saving technology will live forever, long after the people who are temporarily displaced die. You're doing an immense amount of good for the untold number of people who aren't even born yet.
Technology is also global, but the political problems associated with eliminating jobs are problems on a state-by-state basis. Is it immoral to develop a technology just because some political systems are incapable of handling the gains in productivity, while other states are?
If that notion is correct, moving towards an educational model focused around creating the components needed for general entertainment (video/AR/VR/Music etc) might alleviate the problems we'll face.
Where are these people getting the money to spend on entertainment if they aren't working? I don't think this will happen.
What I do see happening, however, is that people have less free time between juggling more than 1 job and a side gig with Uber/their ilk.