No GP is arguing that since the blockchain cannot solve any of the mentioned problems, it does not provide any real benefit. The dispute for companies today are seldomly about whether they signed a contract (the part the blockchain could help settle - though you still need to provide the legal entity -> cryptographic key mapping) but how to interpret the contract and align the legal world(words on a page) with the real world (widgets delivered, machines broken, etc.).

If the problem was about enforcing a signature, you do not need a blockchain, each party to a contract can just store the cryptographic signature themselves or with one or more trusted custodians. That is a fundamental feature of cryptographic signatures not blockchains. And then you need some mapping from legal entities to public keys, but this might as well be a centralized database run by the government (potentially outsourced to a private contractor), after all in many jurisdictions the government already keeps a list of legal entities and metadata about them.