How's this for overthinking...
Sure, if we don't have an invite now, our odds are pretty slim (ie there are only 15-30 slots for thousands of applicants). But HBS has already hand-picked hundreds of all-stars, significantly weakening the uninterviewed applicant pool. So with these final interviews today, we can take solace in knowing that we are marginally more competitive for these last few slots than we have been at any point in the process.
so basically, yeah, we're not going to hbs this year.
Isn't it possible that they just read applications say in lots of certain sizes and send invites in the order they finish those lots. Probably they will finish all the remaining lots by today, which has our applications.