From personal experience, pressure and flexibility. The investigator should be put under pressure to produce results quickly justifying further time investment,

From personal experience, pressure and flexibility. The investigator should be put under pressure to produce results quickly justifying further time investment, in addition there needs to be flexibility in the form of alternative projects they can tackle that have a high probability of working. But I think it's crucial that they be allowed to place themselves under that pressure, if they truly believe they can accomplish whatever big thing it is. And if they have a really good reason that can be written up, that itself is a result that justifies further time investment. I think current science eliminates the possibility of that pressure, and focuses on the high probability projects. I think places like Google X actually don't put enough pressure on, though I don't really know that organization very well.