For example, do the motors in hard drives fail anywhere close to 1% a year in the first ~5 years? Backblaze data gives a total drive failure rate around 1% and I imagine most of those are not due to failure of motors.
But the neat thing about my argument is it holds true regardless of the underlying failure rate!
So long as your per-motor annual failure rate is >0, 43x it will be bigger than 3x it.
For example, an industrial robot arm with 6 motors achieves much higher reliability than a consumer roomba with 3 motors. They do this with more metal parts, more precision machining, much more generous design tolerances, and suchlike. Which they can afford by charging 100x as much per unit.
For example, if you're making a phone that is going to be sold around the world, then you're going to worry about arctic/equator temps (will some of your components melt or ICs fail), salty sea air (will the product begin to corrode for people living by a beach), or fast moving elevators (will the speakers pop from a sudden change in pressure).
You can check out this manufacturers robot arms as some examples of existing products. They list some data sheets for their robot arms, including some arms that are IPxx rated. I don't think looking at robot arms is a 1to1 comparison for what you could expect from a humanoid robot since the considerations in the design process are going to be different.
website is kuka dot com/en-at/products/robotics-systems/industrial-robots/kr-agilus
For example, MIG welding robots tend to life a hard life. And if you look at photos of industrial painting robots, you'll find they're often fitted with plastic smocks.
If you look up photos online you'll only get marketing images from robot makers, where everything is shiny and brand new - I can assure you, it's not like that after they've been operating for a decade or two :)
If the dust collection was disabled, the workshop and the machine would be caked in debris.
It doesn't move, it doesn't fall over or have anything falling on top of it either (like a robot could).
Plus they'll likely be modular and able to be replaced.
IMHO, the bigger design issue for humanistic is lowering the need for mechanical precision which requires lots more metals and instead using adaptive feedback and sensors to obtain accuracy similar to how humans and animals do it. AIs should be really good at that, eventually. I think the compute will need to be about 10x what it is now though.
Assume every motor has a 1% failure rate per year.
A boring wheeled roomba has 3 motors. That's a 2.9% failure rate per year, and 8.6% failures over 3 years.
Assume a humanoid robot has 43 motors. That gives you a 35% failure rate per year, and 73% over 3 years. That ain't good.
And not only is the humanoid robot less reliable, it's also 14.3x the price - because it's got 14.3x as many motors in it.
[1] And bearings and encoders and gearboxes and control boards and stuff... but they're largely proportional to the number of motors.