>If I didn't have house chores or a commute, then I could spend a lot more time learning new pieces of Mathematics. Or work through the rest of the half-finished anatomy textbook on my bookshelf. Or finally get around to building a digital simulation of a human heart. Or start a garden. Or just hang out with a coffee at the hackerspace or coffee shop or church basement.
> There are a lot of opportunities for serendipity, many ways to build grit, and infinite opportunities to socialize.
Indeed, you would technically have more time to do these things. But you would not necessarily know you want to do them, nor find the time to sit and ponder. Not if every moment has been optimised to speed you through your day and onto the next productive task.
Perhaps, you argue, we would realise such moments are important and build them into the system, leaving patches of "hard reality". But we have already begun the process, and the activities you cite are so far faring badly. Putnam and Murray (Bowling Alone/Coming Apart) have both shown how the last half century has eroded actual participation in the activities we have been freed to do more of. They also show that it is hurting us, particularly anyone who is not bright or rich.
Ultimately, we need both the time to build grit, socialise and be serendipitous, as well as the moments of frustration and boredom which allow our minds to wander to such possibilities.