I think the key point that crypto-enthusiasts often miss here is "Are the entities with write access having a hard time deciding who should be in control of the

I think the key point that crypto-enthusiasts often miss here is "Are the entities with write access having a hard time deciding who should be in control of the data store". For many purported use-cases for blockchains (things having to do with traceability of goods for instance) the answer to this question is most likely "no". For instance if you want to trace a shipment of pineapples there must be some entity somewhere who's tasked with making sure that the goods are up to code (otherwise anybody could just lie on the blockchain). This entity is clearly "in control of the data store". Of course you may want to be able to publicly audit that entity's records to detect any wrongdoings or suspicious activity, but that doesn't require a blockchain at all, simply having a signed public database/log (that anybody could archive) would do the trick nicely for instance.