I've been in many 15min meetings that I felt were a good use of time, cause everyone was involved the entire time and the topic was important. Not so many 30min ones; those usually end up being 2 people talking while the rest spectate.

The 2-pizza thing coined by Bezos means 6-8 people.

Three minutes being the sweet spot for me comes with some conditions. For one the team has to be remote first, or real good at async self-organising anyway. One aspect of that is that people show up in the video conference before the meeting starts and do the social idle chatter about sports and television or whatever in advance.

I'm guessing most of those fifteen minute meetings had a set topic, or agenda as I called it previously, and ended as soon as it became clear that it wouldn't be immediately productive or the relevant decisions were made. I've been in many, many fifteen minute meetings where someone spent the entire time in palpation for something that could drag it out for even longer.

It's not uncommon that people are brought into meetings to basically engage in parasocial comforting of someone in a position of leadership they don't have the maturity or competence to perform in, in organisations that did very little to support their assigned leaders. I find this practice quite offensive and that moving away from such ceremonies to people calling a meeting making clear in advance what they want answers to and giving the participants time to prepare paves the way for trust, accountability and flexibility in the work that allows the team to respond better to challenges.