What I've run into as well is free software, where the source is available but the process of building it into something usable would take "months" of work, and

What I've run into as well is free software, where the source is available but the process of building it into something usable would take "months" of work, and the internal toolchain (old software versions, patched packages, etc) is only vaguely documented. Effectively, it's a 'moat' around the business, and allows the business to get the best of both worlds: association with the open source community, and effectively proprietary software. The actual business plan can then treat the software as an exclusive asset (not in a technical, legal, sense, but de facto for sure). I'm not saying it's a bad model; it's probably one of the few that can provide a reliable income, and it gives outside developers a 'fighting chance' at accessing the value of the software.