Re: I've come full circle, BTC is the only worthwhile cryptocurrency
If there was somehow, a far better piece of decentralised distributed ledger that is invented in the future, this can just be forked into the Bitcoin network and the existing data is retained, or the Bitcoin data is transfered to the new distributed ledger.
exactly this was suggested when "Directed Acyclic Graph" chains were newly proposed.
Proposed by who? A Core developer?
no, it was Sergio Demian Lerner's concept. Although arguably it's just an evolution of the "tree-chain" concept, which was proposed by (former?) Bitcoin dev Peter Todd
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A big problem was how to mine using a chain that's really structured like a tree, how do you arrive at consensus on newly distributed money? And of course, the answer was to start with a satoshi style PoW uni-chain, mine all the coins, then fork to a DAG chain once there are no new coins left.
That proposal is a little naive, isn't it? We've already seen what kind of drama the community had with the scaling debate. That proposal would be like nuclear war if taken seriously.
that was my idea
(but maybe Peter Todd suggested it as part of tree-chains? Not sure 
) But it's really just a potential solution to the "2140 problem"; when the block subsidy ends, how do we incentivize mining new blocks? So it would seem like inducing armageddon for no reason if it was proposed to be rolled out any time like today, but 2140 is not today 