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.
As for stability and predictability, I’m not confident that AAA apps are hugely (or maybe even significantly) more stable or predictable than the best games. Maybe my tolerance for bugs is higher in games than apps, but I do seem to tolerate quite a lot of jank and slowness from apps, so I’m not sure.