Maybe I'm one of the stupid ones, but isn't an asset's value determined by what people would pay for it on the open market (among other things)?
No, that is called the cost. Value is something different. I'd suggest you read some of Warren Buffet's writings to help you understand the difference.
... (the ... part have nothing to to with this, I'm not taking anything from the context)
What was the value of gold 10 years ago? was the price that people would pay for it. It wasn't the cost, it was the actual value. Same as BTC 2 years ago, same as oil 1000 years ago, it had no value because nobody was willing to pay anything for it. Maybe in the future we discover that we can make gold from iron and it's value plumets. It's it actual value that plumets, not the cost.
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Something can have value for me but not for you. For example I may be willing to pay $1000 for something without any value for you, like my dog, if I loose him. What is the cost of the dog? The value is the real indicator of value, not the cost.
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