Which is to say I think starting with the idea that you're aim for x10 is pernicious and tends to create dysfunctional teams. The claim some developers in some circumstances are ten time more productive than others may or may not be true but software development needs processes whose goal is to help an entire team rather than helping an individual to that "level".
Developers should strive to better themselves, but it's important not to fool yourself, too. Having a strong team is almost always better from a business point of view.
I shun "rockstar" and "10x" (and whatever other bullshit moniker they will come up with next) team members. Give me a group of smart people that gel well together, and are highly self-confident without egos getting into the way, and we can move mountains.