Ranger was a last-resort Pacific substitute

If Britain had not loaned HMS Victorious, would the United States have sent USS Ranger to the Pacific?

It could have, but the U.S. Navy strongly preferred not to and used Allied carrier availability to avoid that choice.

USS Ranger was a technically available but unattractive substitute for the British carrier HMS Victorious. American planners made conspicuous efforts to keep Ranger away from the Pacific's more demanding carrier war. An extra surviving British carrier could cover Atlantic duties and release a more suitable ship for another theater. Carrier availability therefore compounds across alliances, because one ship's presence changes what several other ships are free to do.