I'd tend to agree - even leaving aside the thrill coaster aspect aside, Disney have too much demand currently and have been busy trying to price folk out of coming to their parks by jacking up prices and introducing Genie plus....and still the masses flock to their gate!
If anything another park in orlando to take away some foot fall would probably do them a favor, at least in the short to medium term from a guest experience perspective!
Disney seem to have more visitors than their parks can cope with without notably degrading the experience, so I doubt they plan to invest big in response to Epic Universe as they probably dont feel they need to with current visitor numbers .....they can probably afford to loose some foot fall as long as they continue to increase the spend per visitor