I don’t think that it’s as common today, and it’s definitely not common in the open-source-oriented software world that I tend to inhabit, but I do remember seeing the phrase “proprietary technology” used in a positive sense on various products in the past. Maybe 1990s or so. The idea is, I suppose, that if the technology is proprietary, this is the only product where you can get it, and the implication is that it’s better.