Every place has had some experience with some problem that entire different teams, with dozens or even small hundreds of people failed to solve for years and years, and then some individual came and did it.

And almost everybody has seen or heard some similar story.

The thing is, those stories don't have a lot of similarity to each other, and there isn't much you can conclude for anybody's competence without looking at all the details. But they happen all the time, and not only in software development (just not on the same frequency, for obvious reasons).

"One solo dev who achieves as much as a N-person team" or alternatively, "N developers who achieve as much as a 10*N person team" is the one most easily supported with evidence. Prior to their acquisition, WhatsApp had 55 employees of which 32 were engineers. Facebook Messenger had a team that was most likely 100x larger than that. In 1995 when Microsoft effectively defeated IBM as the premier software company, Microsoft had just 17,000 employees to IBMs 225,000 employees. The entire reason why a startup can even succeed is because a smaller, skilled team can overcome a much larger team with much more resources.

Microsoft headcount vs. IBM is not a valid comparison. IBM is also a hardware company. IBM is also a service company. And IBM (at least at that time) did far more custom development than Microsoft. You'd have to compare the headcount of Microsoft's OS business to IBM's OS business (or OS development organization, if it wasn't a separate business).

I don't think listed options are "different scales" - they seem similarly "out of reach for normal people" just in different directions

Nowadays a single solo dev can outright achieve as much as entire _organizations_ could in the early 2010s. I know multiple people whos raw code output easily exceeds say everything Amazon/Google/Facebook (likely combined) could do in a single year in the 2010s.

Imagine a gaussian distribution of all engineers. It's a figure of speech to say someone's productivity falls in the right-side tail of that distribution.

The multiplier isn't meant literally. It's shorthand to say someone is exceptionally good in a way that is rare to find.

You're right. That's precisely the problem. The "Nx Engineer" is catchy and we all know "what it means" when we first hear it. We most likely relate it with an early experience when we were juniors and a senior developer pair programmed with us. For me it was mind-blowing. So we can relate to it.

But the issue is the ambiguity. The multiplier is there, but not the unit/metric being measured. So it's just a shorthand for "someone exceptionally good" as said by a sibling comment.