The only thing I can tell to a critic is this: Bitcoin is the technology; not blockchain.
bitcoin is the first flagship, hero, famous currency and the first and main hero,famous "brand" of the technology of blockchains. but the blockchain is the main technology that provides the decentralised archiving, auditing and the ability to allow many features within it. blockchains openness to change the features within them allow people to create many altcoins, which is a feature of blockchains tech (not 'bitcoins' tech)
changing the things unique to bitcoin creates altcoins. but those altcoins are still based on the blockchain outer technology
bitcoins uniqueness is in the halving rate(deflation/supply/scarcity) the PoW(underlying value/security/immutability) the unit amount(supply/scarcity) .. satoshi choosing 210k block halving as a number, choosing sha2 as the PoW algo. choosing 5,000,000,000sats as the genesis release amount and calling a 5billion sats/100,000,000 a "btc" are things that make bitcoin bitcoin.
different altcoins have different options/choices
blockchain features like the block Id based on a "sum" of the content, chaining of blocks via the Id's of previous blocks, allowing them to be archives remotes/decentrally while easily comparable by just comparing block Id's
is the blockchain tech stuff
taking away the unique things of bitcoin like the sats.. like the PoW, like the sha256 of pow, .. makes an altcoin,
take away the tx/spend structure and replace it with a file hash index structure creates other things that are not altcoins but still use blockchains
where the more you change the more you make an altcoin or other token/auditable structure, which is less and less like bitcoin...
take away the blockchain. creates things even less like bitcoin and altcoins. like them smart contract networks that connect between many blockchains that have no consensus or network audit. nor even use units that even resemble bitcoins or altcoins. where even the message formats that go between peers is completely different. makes them less and less like bitcoin
you cant take bitcoin out of its blockchain.