I think the OP's point is that if you took someone from 2000 years ago, they would never believe that! They could not imagine those progressive improvements intelligent beings had made, from simple minerals in the ground. They would only see the final products, and probably be convinced that they are all "irreduicbly complex", could not have possibly "evolved" from dirt, etc.
I think the conclusion those time travellers would make about our hi-fis and cars is that they were designed using intelligence.. the only disagreement possibly centering on whether that intelligence be divine or human.
I don't think any reasonably intelligent time traveller would conclude that the hi-fi or car came about gradually over time through random progressive increases in comlpexity.
Presumably the mechanism would have to be strong winds or floods or something of that nature; capable of moving dead bits of matter about and rearranging them randomly without intelligence.
Say I put a hi-fi in a barrel, then I put several 'improving' components along with their wires into the barrel with the hi-fi. (It's an equal mystery where these 'improving' components would have come from too)
Then I close the barrel top. Let's say the hi-fi will buzz when it has been upgraded, to let me know.
How many trillions of years would I have to roll the barrel around before those components would become attached to the hi-fi in the correct places, in the right sequence and with the right wiring?
After say 10 trillion years, getting a bit tired and hearing no buzz I'd stop and open the barrel. Instead of a new improved hi-fi what I'll have is a pile of dust.
The same applies to life. Except that the simplest form of life is enormously more complex than any hi-fi.