Not sure what you mean by the "protocol". Ethereum, like many cryptocurrencies, is open source. So you can fork it, change it, and build your own system. Now

Not sure what you mean by the "protocol". Ethereum, like many cryptocurrencies, is open source. So you can fork it, change it, and build your own system. Now your system needs a network of nodes to support the blockchain. How else do you incentivize them but offer them block rewards in the form of tokens/coins? Unless you don't want to be decentralized, which is totally possible. But why would anyone want to use your product if it risks being shut down so easily? So whatever your network is, now you've got traction and you're running into scaling problems. You want to implement new features. Are you really smarter than Vitalik Buterin? Is your team better, can you actually solve those problems? If not, isn't Ethereum ultimately better than whatever is trying to compete against it? Private blockchains could have a place solving niche business problems. But whatever that solution have far more advantages existing on Ethereum vs elsewhere.