These businesses are building private solutions using their own forks of Ethereum. How would this affect the price?
Because this decision by "these businesses" represents a major endorsement of the Ethereum idea, application of the blockchain, and platform. And the Ether represents shares in that movement, although I know it is not legally or physically shares in anything more than the currency Ethereum is using for entities to interact on the platform.
If the Bitcoin ETF had been approved we would have seen a run up of Bitcoin directly correlated to that news.
Investors buy on the news (either real or speculation), and that's what's happened with ETH.