I appreciate how you feel - sometimes it really is the luck of the draw. From many friends applying, I know pretty much every combination of people who got 1/2 MBB interviews (e.g. Bain and BCG but not McKinsey, McKinsey but not Bain/BCG etc.), which just goes to show how random/up to chance it can be.
However, there are ways to maximise your chances. Of course you need to have actual strong experiences, which it seems you/your friends have. The next step, though, is how you present those experiences. The same work/leadership experience on a CV, depending on how it's presented, can make a CV go from mediocre to excellent. Some general tips:
-Focus on Impact/"So what", not process or details: Especially for Science students, I have seen so many CVs that just talk in detail about the experiments they ran without any clear mention of the impact/"so what".
-Focus on impact YOU had, not the team: Of course we don't want arrogant people at Bain, but a certain amount of bragging is necessary. It's no good to say "worked on the TMT deals team" - tell me specifically what YOU did - e.g. analysis, presentation, data collection, client meetings.
-Keep it to one page, and have a succinct cover letter: Too many times I have seen 2-3 page CVs filled with loads and loads of details about every project the person ever worked on. This is bad because a) the reader will instantly disengage and b) it actually will take away focus from the strong experiences you actually have. On the cover letter, I have also seen my fair share of 800+ word cover letters - again, here, this is just too long for someone reviewing 50+ applications to read and digest. Keep the cover letter short and to the point - I usually recommend about 400 words.
Sorry for the bad news, but you should not be discouraged from reapplying - Some people I know at Bain only got in after their 3rd time applying!