No. Stop making things up please.
Looking at the source is just copying off of someone and you claim it as your own.
That's why people can't do anything with sources unless it was written in a way you can recycle it which is rarely ever the case.
3. If you look at the novice forum (whose topic owners are also the most likely to use open-sourced engines), quite a few users are confused at even the simplest constructs of GML. Open-source code is of no use to the large amount of GM novices who can't understand them.
5. Most GM projects are managed by a single person. That way, only one kind of logic gets into the game. Anyone else trying to read the logic will have quite a bit of figuring-out to do, which is simply impractical for most medium- to large-scale projects.
Noone cares about those rating numbers. Why do people think anyone cares about those rating numbers?
I rate this topic officially 1/5 (yes I like rating topics )