Keep in mind the definition of 'work': Bitcoin was originally intended to be a day-to-day medium of exchange, not a 'long term store of value'. It's much more of a threat to governments as the former but that really hasn't actually panned out (including in the places you mention), and it's just a random speculative asset which financial systems will toy with like any other.

> So, has trump coin and world liberty financial proven your friend wrong?

No:

1. That's not being implemented as a permanent replacement for typical currency, that's cryptocurrency as a specialized temporary vehicle for accepting bribes and fleecing the gullible.

2. Even if #1 were not true, it's rather hard for a democratic government to react when key positions in that government have (temporarily, I trust) been taken over by a cult that profits from the scheme.

> It seems that it was you who misunderstood human nature. Greed always wins.

That's an inaccurately nihilistic view of what "human nature" encompasses. If greed always won, nobody would have pets, charities would not exist, parents would enslave their children, life-insurance would just be an invitation to filicide, etc.

>What about El salvador or the cayman islands?

What do these prove? some people dodge taxes?

TrumpCoin and WLF are obvious grifts by parties associated with Trump and not actually part of government policy, and the president is not a rational actor trying to maintain a capable government.

El Salvador's experiment was generally a failure for various reasons, and they agreed to start rolling back the policies as part of an agreement with the IMF for another loan.

These projects happened because, yes, greed wins and destroys everything in its wake.