Outside of Bitcoin, if a company set up a blockchain like structure that can be publicly accessed but only the company itself mines blocks, does that mean the blockchain can't be trusted?
I have only a rough theory in mind, no hard examples. Say a card game was implemented using a block chain. Card collections and game stats are stored in a blockchain and accessed by all the players of the game. None of the players mine any of the blocks. As players play the game, trade cards, open booster packs, etc they submit varying types of transactions to the company and the company verifies and adds the data to the blockchain. But the company mines the blockchain to solidify those transactions themselves and not allowing clients to mine at all.
I can see how money (Bitcoin, fiat, etc) would change hands for rare cards or booster packs. Inherently there would be value for the cards not unlike Magic: The Gathering or Pokemon having rare cards that people want. Can a player trust the company's blockchain? Since the number of miners is controlled by the company, what would be an acceptable difficulty for the miners to have to reach? Wouldn't too low of a difficulty not be enough proof of work to be trusted?
Since it's in the company's best interest to promote the proper use of the chain it's not really a 51% attack (technically a 100% attack). The users would know they're not mining from the beginning. Would this be any different than the company choosing postgres over MySQL? It's just the company's choice for storage, right?