Part of that is probably that game developers tend to be passionate about the work they do, whereas most people working in app development probably don't give too much of a shit about the boring apps they're making. It's hard to get motivated when you're just making a glorified front-end to a database, another e-commerce site, etc.

Of course, the tradeoffs in work-life balance for game development is massive, so it's not like that extra productivity is free (unless you're management). Nobody working at a typical software firm is going to be expected to crunch 12 hour work days for weeks just to ship.