it will last minimum another 5 year.
It'll surely last longer than that, question is what will the value be. It's not going to magically disappear after 5 years.
Like Cortana said ir will last 500 years

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Now serious, i think price will only go up. New people getting into it, and its harder and harder to mine. So that what is mined need to spread up, and price will go up.
Indeed. But we might encounter unexpected problems in the future. Or we might not. We'll see.