Earlier quoted context omitted.
I've always thought that this is the key to bridging the gap between proprietary and OSS, and it's what we do with our software. In our case, the source code does cost extra, but that's because we're selling developer libraries and we typically need to provide extra support to customers that purchase the source code because they are also (typically) customizing the source code in some way.
I really like how Epic is handling Unreal Engine 4. The source is available, and the standard license is revenue share. It's not necessarily open source, but it reaped so many benefits from public contributions. You can modify it and extend it for your own use. The revenue share means they are actively interested in your success. Of course video games are highly public consumer products. So you can't actually abuse t…
For larger companies in larger markets, it's much, much easier to see when someone is abusing a license or pirating the software without paying.