Is money that has gone into bitcoin already spent? Is money that has gone into bitcoin already spent? When I buy a bitcoin from someone and they get USD I get bitcoin. They go buy lambos or real estate for their gains. So the underlying currency is spent, but BTC market cap is increased. This would mean that cryptos don't actually have any real money in them and they could collapse without bottom basically. Is this logic correct or is real really currency as value behind crypto?
As @RedGrittyBrick says, change the word &quot;bitcoin&quot; to &quot;euros&quot; and see if that helps you. All currencies work this way, not just cryptos:

Is money that has gone into euros already spent? When I buy a euro from someone and they get USD I get euro. They go buy lambos or real estate for their gains. So the underlying currency is spent, but euro market cap is increased. This would mean that euros don't actually have any real money in them and they could collapse without bottom basically. Is this logic correct or is real really currency as value behind euros?

And someone in Europe probably has the exact same question about USD.
All currencies are fundamentally worthless. Except for things like gold, which you can use to plate the contacts of electrical switches, coins, which can used as paperweights, and paper notes/bills, which can be used as toilet paper.