Right now I am living the opposite, consulting to a huge company where anyone can convene huge meetings with no agendas, especially if they are a compliance person, or product person.
We have many, many meetings where many people have no idea what the meeting is about, or even worse they will talk about 3 or 4 different topics.
They also practice what I call Rumor Driven Development. It is not fun.
In consulting you tend to encounter this a lot given that its the largest visible symptom of a lot of root problems such as: 1/ no owner 2/ unaligned priorities 3/ a lot of fear or lack of ownership mentality
Generally I push for an agenda and an owner of each topic (or all topics) and a recap, preferably in a transparent location like confluence. Given all the synthesis tools in the market, synthesis has gotten easier.
I also generally push to have leadership realize how costly each meeting is and encourage people to excuse themselves from meetings if they are not: owners, influencers, stakeholders.