These fork-like efforts are able to take the risk of the experimentation without putting the mainline project at risk, and their successes allow the supporters

These fork-like efforts are able to take the risk of the experimentation without putting the mainline project at risk, and their successes allow the supporters within the original project to point to it as a viable path and gain the needed mindshare to pursue something achieving the same goals. It's a similar model to larger corporations allowing innovation to occur in startups and then buying them out once the model or technology is proven to a degree.