Some will always see an assembly as an institution. Also, the longer something remains, the more institutional qualities it takes on. Some churches handle that reality better than others.
Yes, but isn't it a fact, that the bigger they grow, the more likely they are to collapse? Where have all the churches, so swelled with members, in the 1950's gone? Where are these mega-churches of today, headed for? They will break up and disappear, or some sects will remain. Corruption seems to be built in to them. And if that is so, then they must not have been founded on the true rock.