$20 in 1891 is ~$500 today. I'm sure the iPod nano could be an heirloom-quality device if you were willing to pay $500 for it. The photograph was certainly not

$20 in 1891 is ~$500 today. I'm sure the iPod nano could be an heirloom-quality device if you were willing to pay $500 for it. The photograph was certainly not maintenance-free so for equal comparison we have to assume even with a massive over-subscription of flash you'd need to replace the memory every 10-15 years. The battery probably every 5. It's a difficult problem to reason about because our own perceptions are anchored to what we know. You couldn't have had a modern home air conditioner at any price in 1891. Ten billion dollars couldn't have bought you the computing power of a MacBook Pro in 1950. The quantitative and qualitative gap between successive generations of computing technology is many orders of magnitude beyond what any other technology has ever experienced in human history, and the generations themselves have happened orders of magnitude faster too. I don't even know how you compare these things in economic terms because the baseline equivalence between products is nonsensical to start with.