[nradov]

The metric for success on any commercial software is long-term ROI, not "fun" or "functionality". This applies to both games and business software. Fun and functionality can't really be quantified in a way that's consistent or comparable across products.

Some of the most successful games aren't really much fun for the most active players, such as MMORGs and free-to-play mobile games. They seem to succeed more through triggering addiction and a sense of competition amongst players rather than providing an enjoyable experience.