Arguing that it's the majority that is 1/10 as effective as the best is like
saying somebody that he's ten times stupider than Einstein. It might be
technically correct, but it misses the point: most of the people employed as
programmers are bad at writing code.
I've been a 1/10 developer and probably still am for some tasks which I work on. I think that EVERYONE is a 1/10 developer at times, especially when trying doing something new or difficult.
I would be interested to know exactly what kind of project can be completed in 30 minutes by a 1x developer that would take a relatively intelligent 1/10 developer 3+ weeks? That sounds like BS or exaggeration, it smells fishy.
The fact is there aren't enough developers to go around. As a result, any shop that cares about long term productivity needs to invest in cultivating good ones. That means giving time for a learning curve.