[us]

Because developers greatly benefit from participating in open source projects, designers usually don't. That said, developers also make more money than designers do and in a tech centric world, there are more needs for devs than designers. That's why.

[nir]

For most OSS devs, the benefit is having a more interesting portfolio, especially skills they don't get to use in their day job. Wouldn't this work the same way for designers?