I must really be getting OLD!

I just don't see myself in a scenario like the one you described anymore.....in a group like that, at those speeds, for that distance, mechanical issues would have been my least concern!
Don't mean to be a downer, and it sounds like you had a great time, but the ride you describe is why I ride alone or with MAYBE 2-3 other guys anymore, and even then it has to be fellow bikers I have known for years and have the utmost confidence in their riding skills.
And THEN, being the old man I have become, I insist we maintain a cruising speed no higher than 65MPH. There just ain't NOWHERE I'm in that much of a hurry to go anymore! (Except home to Cat and my sons after work, but that's only a few blocks away!) Speeds in excess of that self-imposed max just take the relaxation out of riding........my white-knuckled hanging on while praying nothing even tiny goes wrong, (because at those speeds, especially with a large group of close-quarter riders some of whom may be slightly inexperienced, a tiny mis-step will almost certainly end in a catastrophic disaster) are OVER for THIS old man!
Please understand....no knock here on your ride.....YOUR choice Bro!
After 40+ years of riding, and for years riding with a large MC, I've seen the consequences of those high-speed close quarter long distance rides end "not well" all too often. Like I said, maybe I'm just getting old, but it's just not for me anymore!