Pure speculation, but in that reversal, I think the Japanese carrier planes would have finished the job by sinking our battleships at Midway, since those would have been all we had to send there.
Or not - could be the fleets never would have found each other, the Japs would have bombed the crap out of Midway virtually unopposed and then landed and taken it.
Either way the Japanese would still have had their carriers to harass and interdict our attempts in the Solomons, etc. etc. Or we would have had to wait until we built new carriers before trying any island landings.
I think we would have won eventually since it was a war of attrition after all, but there would have been lots of ripple effects that would not have been good for us, that's for sure.
What if's are fun, but we should all thank our lucky stars that the Japanese DID miss our carriers at Pearl, and that we fortunately did find their carriers at Midway and by sheer luck on our part and a bad decision on their part, that our dive bombers arrived when their carrier decks were loaded with planes being re-armed.
Lots of places where history swung on one lucky (or unlucky) happenstance.
