Originally Posted by strim
Consider this: if the Blitz stayed closed, would it receive any updates at all? I highly doubt that. Thanks to it being open, at least some parts were fixed, extended, reworked and so on. OlafSch and WxR made a point before me.
While open source might not be the "silver bullet", it at least allows people to contribute. The mentioned opportunity is most important. If you don't give people this opportunity, they can't do much with broken closed source software. There's no guarantee they will do anything, but it's always worth trying.
Closed source also allows people to contribute: by writing a replacement from scratch, free from the constraints of the original.
Doom clones didn't wait for Id Software to release Doom's sources to appear.
These guys coded their own.
If there are no coders motivated enough to start a replacement for <Insert-Your-Favorite-Project-Here> from scratch it is unlikely hat there will be many to fork and maintain an open source version. In both cases you need a full team to produce new content so if that team does not exist now, the existence of open sources is not going to make it appear magically.
UAE is open source and is a fantastically important project: how many contributors? Not even a handful. (Thanks Toni for your dedication by the way!)