Probably a cultural thing. I don't see a problem with this. Depending on the meeting, there is no way it will end in 15 or 45 minutes. If it finishes earlier,

Probably a cultural thing. I don't see a problem with this. Depending on the meeting, there is no way it will end in 15 or 45 minutes. If it finishes earlier, great! everybody goes back to work. Sometimes it goes longer, and people have to check if it's being productive, or if they need to gather more info to come back later to subject. 30 minutes seems ok for a meeting. Lower than that, maybe you don't even need a meeting. Just some chat in a slack group.