Same with open source. The more open source exists, the easier it is to make more useful open source, which increases the surface area of profitable development, which fuels more open source.
1000 programmers is more than 1000x as valuable to the world as 1 programmer. A million may be more than 1000x as valuable as 1000.
The last statement is utterly wrong, and is wrong for most fields of endeavor.
One programmer on their own has the maximum possible productivity per person because there is no communication needed. The whole project sits inside one person's head.
Of course, real world programs usually need more than one.
Each new programmer that is added also adds a little overhead to the existing programmers.
More, once the project starts to get really large, you start to get new forms of time wasting.
In a project with 1000 programmers, there is bound to be a huge amount of duplication, quite a lot of programmers working at cross-purposes to other programmers that they don't even know exist.
And there will also be programmers who do nothing, and get away with it in the mass.
And this is particularly true in open source, where there isn't any strong management at the top trying to prevent duplicate work.
1000 programmers is more than 1000x as valuable to the world as 1 programmer. A million may be more than 1000x as valuable as 1000.