I figure yeah, table size, plus convenience in arranging parties. Getting four people together isn't too hard; getting more than that, you start having the problem of "where do you want to eat tonight?" and "how do we fit all our crap on this stupid table?"
(Says us who only ever played D&D with one to two other players. But hey, I've seen my friend try and play the "fit my D&D party of 5ish around the table" game, and it was no small feat; he had to take EVERY SINGLE CHAIR in the entire apartment and rig them around a mound of small tablelike objects, none of which were had the same height, and then try to make it so everyone could get OUT once they were settled in. It was NOT easy. Four people, though, you can generally fit around your average table, or in an easy square configuration on the floor.)
no subject
(Says us who only ever played D&D with one to two other players. But hey, I've seen my friend try and play the "fit my D&D party of 5ish around the table" game, and it was no small feat; he had to take EVERY SINGLE CHAIR in the entire apartment and rig them around a mound of small tablelike objects, none of which were had the same height, and then try to make it so everyone could get OUT once they were settled in. It was NOT easy. Four people, though, you can generally fit around your average table, or in an easy square configuration on the floor.)
--Mori