The myth of the “10x Developer” (a developer that is 10 times more productive than the average — the unicorns many startups believe they need to succeed) is rooted in pure technical fluency and short-term growth metrics. Someone who deeply understands their language & stack can create greenfield code extremely quickly. This is the narrow goal of most startups with venture funding. They often don’t really know what they’re building, so iteration is valued above all else.
This isn’t the same thing as a developer with experience working in a team, leading a team, working cohesively as part of a business unit, or building in a similar product domain. All of those pressures will show up later as fissures in past work of the “10x” developer: worse bugs, increasing overhead, and diminishing options. This sand in the gears accumulates on the scale of about two years before you truly start to notice it. Five years is when I suspect it usually becomes flagrantly obvious.
Thus a “10x” developer in a startup can be worse than 1x on a longer timescale, snd so it matters how you’re measuring a developer’s value. If you slice 6 months of “achievements” as your metric, you truly have no grasp on what the holistic cost-to-benefit ratio of their long-term employment is.
An experienced developer that moves slowly initially and gauges possible solutions against their potential outcomes relies on progress that gains momentum over time, as their confidence working within the system grows and long-term benefits are reaped. This is an unsatisfying narrative for many managers.
An inexperienced, technically-fluent “10x” developer conversely may sense their own diminishing momentum and endeavor to move to a new stack or product domain where they can replicate their previous speed instead of investigating and patiently remedying the cause of the slowdown. This obscures their real cost and inhibits their growth.
Being a great manager requires not only developing the ability to consistently differentiate the two, but the ability to get them to work together effectively to their mutual benefit.