There have been cases where it really sounded like there was a traditional split along the court and then some questions pop up and the answers are so bad / arguments clearly absurd / the lawyers have no good answers that suddenly the case is clearly going one way.
Usually this revolves around the sort of second order effects of a potential ruling and where ideology isn't entirely clear / has some conflicts with those second order effects.
In fact, I think it would be a bad thing if the court swung on oral arguments. These are very complex topics prepared by an army of lawyers on each side. They should not hinge on if a single presenter doesn't have a clear an concise answer within two seconds of being asked it.
As for the rulings there's A LOT more than ruling one way or another, the ruling itself can range in all sorts of directions.
They are limited to 1 hour. You have 2 or more parties giving opening questions. And the 9 justices questioning each on what are often thousands of pages of documents.
It is really more of an opportunity to publicly critique each side with a few pointed questions.