It's a pretty weak analysis and they don't source that claim or qualify it. By revenue, there are several big AAA titles with proprietary tech, and a handful o

It's a pretty weak analysis and they don't source that claim or qualify it. By revenue, there are several big AAA titles with proprietary tech, and a handful of top mobile titles as well. I'm guessing that's the analysis they used. Only the very largest companies can justify their own engine these days - Activision, EA, Ubisoft, Riot etc. And most of those engines date back decades. You'd be hard pressed to justify building your own engine tech starting today. An analysis by revenue isn't really very meaningful today because of the historical head start those companies. Their ongoing franchise revenue distorts the analysis.