To each his own, but that hasn't been my experience. I estimate that at least 70% of my maintenance time is due to tires/tubes and another 10% to brakes. Eliminating the gears would only have rather minimal savings in maintenance effort.
Taking off the multi-gear related components would save me at most 2 lbs. so the bike weight would drop from about 24 lbs. to 22 lbs. If I'm carrying loaded panniers the impact would be even less - from 44 lbs. down to 42 lbs.
Neither benefit is worth giving up the convenience of being able to stay in a comfortable cadence range across a wide variety of terrain and wind conditions.