Largely I thought that this is what you do once you're established in math (or any field) anyway. You have some ideas, but the details are kind of too tedious for you to work out, so you give it to grad students/postdocs. Senior engineers have some ideas, but the details are tedious to work out, so you give them to junior engineers.
Now, obviously in the meantime, there's the question of how do we train the next generation? Or do we need to train the next generation? And maybe while we work that out the answer becomes more shadowing/apprenticeship instead of farming out easy tasks.
I'm not confident in that statement, but I think it's well within the realm of possibility. Then again, so is needing humans to architect / steer for another 2 decades. We live in exciting times!
Yours is more likely in my opinion though, mainly because universal high income is completely infeasible and shaky even at the level of definition.