OTUSA win streak is 4.
FWIW, Emirates longest win streak in the series is 3, which they have done twice. Oracle now has a 3-win streak. And that's in part thanks to the one race exceeding the time limit. So I'm thinking Oracle has another win or two in their pocket.
It was on September 26, 1983 that the Aussies broke the longest winning streak in all of sports. Right now there are no races scheduled for the 26th with 2 today and 2 tomorrow (9/24) but we've seen a lot of races cancelled. So in the Even More Unlikely Scenario category, it would be possible to have the Cup decided again on September 26th.