If you've goon 15 years without any stand-up being under 15 min, then you are doing something wrong. Is your team absurdly large? Is your scrum-master not fluent in scrum? Does no-one in your company understand how a time-box works? Or do you insist on bringing up lengthy technical discussions that you could perfectly well take with the 1-2 people involved outside of the stand-up? There are tons of ways to do it wrong, and pretty much every single one comes back to people not understanding what the stand-up is and isn't for.
It's popular to shit on scrum, but a lot of the criticism comes out like someone going "Programming in C is rubbish, it always throws segfaults, and it's impossible to create good software in a programming language that isn't pure functional" It's an opinion sure, but it's based off of being bad at coding C and preferring to code in Haskell, where you might ask the person if they had considered actually learning C before shitting on it.
> If you are in the middle of something, a 15 minute meeting clears working memory every bit as much as a 3 hour meeting.
Getting interrupted for a 5 min talk with a colleague is just as interrupting to your flow. Don't pretend to claim that everyday in your 15 years of scrum you have accomplished absolutely nothing on a day if there was both a daily standup, lunch, and a person asked you question.
Yes interruptions are bad and should be minimized.. which is why having 15 min condensed to get everyone aligned is better than having 5 people dropping by randomly to ask "did you commit the feature yet?" "Was it me or you who was supposed to do X" "You do know that I'm waiting for you to finish Y right?" "Are you waiting on me to do Z, cause I prefer doing X first, but no-one needs that yet". And again, if a team has more than 15 min total of those kinds of interactions during a day, you need to reflect and improve. If you have less than 15min, then great, everything is cleared up after the daily scrum.