Agile process drowns in meetings: kickoffs and walk throughs

I have noticed this phenomenon during our “planning poker” estimation meetings, and to some extent in retrospectives and other meetings about iterations, planning and progress. Each time a meeting is held, the number of attendees increases slightly, and the meeting (sometimes imperceptibly, but the cumulative effect is there) slows down. This slowdown leads to a perceived idea that if only we had more stakeholders in the room, we could get more answers more quickly, so more people are invited. And so it gets worse.

Chris Johnston » Of kickoffs and walk throughs

Is this a general curse of agile processes, or is it a particular anti-pattern or failure mode which can be avoided?