I’ve seen surveys on what people are doing at random times. Here’s one on what people desire at random times:
208 participants (66% female) … indicated at least one current desire on half (49.9%) of the occasions at which they were beeped and responded (N=10,558), reported at least one recent desire on 26.7% of occasions, and reported neither a current nor recent desire on 27.6% of occasions. The most frequent desires among the total of 7,827 desire reports were those rooted in basic bodily needs: desires to eat (28.1%), sleep (10.3%), and drink (8.6%); followed by desires for media use (8.1%), leisure (7.2%), social contact (7.1%), hygiene-related activities (5.9%), tobacco use (4.8%), sex (4.6%), work (3.0%), coffee (2.9%), alcohol (2.7%), engagement in sports (2.6%), and spending (2.2%; category “other”: 1.9%). …
53.2% of desires [were] rated as not conflicting at all, 14.7% as mildly conflicting, 12.4% as somewhat conflicting, 10.9% asquite conflicting, and 8.8% as highly conflicting. On average,desires were actively resisted on 42% of occasions and enacted on 48% of occasions. (more)
What about the desire to not carry a massive life-support backpack everywhere, or the desire to not have leaked filth dripping down the back of your pantleg? Without mass production based on designs laid out by competent professional engineers, any half-baked plumbing project is going to leak, especially if it's under dynamic stresses.
Don't actual people get most of their sense of meaning from fulfilling those kinds of "miserable thermostat" desires? Are you sure there would be enough subjective meaning left over to satisfy us if we automated the SIMS-style game we play all day?