Originally posted by lynx_lupo
They\'d have to get/update the engine constantly and with time they would grow less motivated(probably).
You know, when you are a part of a coding team, you spend a lot of time trying to understand what your teammates did and how you can use them. Using an external engine is not so different.
And i still don\'t think that a commercial project with 40~100 people goes 10x faster than a free project with 4~10 people. Why? Because PS doesn\'t have (and don\'t really need), commercials, testers (we are here for that, aren\'t we?

), managers... Ok, there is only 10 members in the PS team, but these people work on PS, not on ads nor trying to find who isn\'t enough productive...
That\'s also why they don\'t want to invite everybody in the dev team. A low-skilled teammate can waste the time of all the PS team.