> but "blockchain" is not (only) bitcoin's blockchain, anyone can make one and can validate and replicate it with any group of collaborators or adversaries.
This is a misunderstanding. Yes, anyone can launch any blockchain, but those blockchains would not be secure from attack and are thus untrustable. The "only" blockchain that can be trusted is bitcoins and that's precisely the point, there can be only one winner due to network effects as size of the network is where the security of the network comes from.
A blockchains primary feature is decentralized trustless transactions and that only works when the network is large enough that no single player or group of players can control more than half the network. There is quite literally no point in using any blockchain other than bitcoins as it's the only one with enough scale for the trust to exist.
This is a misunderstanding. Yes, anyone can launch any blockchain, but those blockchains would not be secure from attack and are thus untrustable. The "only" blockchain that can be trusted is bitcoins and that's precisely the point, there can be only one winner due to network effects as size of the network is where the security of the network comes from.
A blockchains primary feature is decentralized trustless transactions and that only works when the network is large enough that no single player or group of players can control more than half the network. There is quite literally no point in using any blockchain other than bitcoins as it's the only one with enough scale for the trust to exist.