Lots of grad-students are "abandoned" with funding and, unless they're extremely extroverted & good at networking, always fail badly.

Employed until retirement kind of hiring was the norm in Japan, with the work over life focus meaning many companies saw their peers more as an tight knit fraternity rather than the dry "strictly business" hiring in west.

So someone with known track record of being diligent and hardworking was often given more chances, even if his work didn't immediately produce result.

You're right that it's not a good one in the sense that for majority of the cases this just leads to bloat and unproductive members sticking around. But many innovations, academic or industry, in Japan, came from people being measurably bad/average in productivity, given a chance until they found their breakthrough. (entertainment industry had a lot of those)