This rigid definition into two different groups of people is pretty absurd if you just spend a minute thinking about it: in what other areas is it really reasonable to define human beings into personality binaries? The common response to this is always "well, it's a scale", like when people say they're a mixture of being introverted and extroverted -- another binary that does not stand up to scrutiny and seems to push the goalposts every time you poke at it, because most people do enjoy being alone occasionally, just like most people do not improve their mental health by avoiding others.
If someone identifies as halfway between a "stable" and a "volatile", that doesn't make them "a little bit of both", it makes the scale useless, because like a flatlander in 3D space it's obviously unaware of an entire dimension of human character and psychology. And yeah, of course these terms are created to "simplify" and "further discussion", but do we really need to put on a red or blue armband before having a discussion?
The picture painted here is one of the "risk takers" and the "risk avoiders", and while it tries its best to paint a fair picture it's pretty obvious it comes from a culturally American idealization of the Maverick, the risk-taking, 48-hour-working engineer who "gets it done(tm)" -- and I get it, that is valuable, and I've worked in companies filled with people who repeat phrases like "it's the way we've always done it", just as I've worked with people who got burned out re-factoring code, didn't care to document it and then quit, all in the name of this creative explosion the post seems to imply -- but if I can take anything from this post, it's not that these are natural laws of character that will repeat until the sun goes out, but rather that anyone solidly in the "stable" or "volatile" camp needs to work on their character progression to learn more from the other camp.
Nobody is born or raised into a role and then doomed to play it out for the rest of their life, we are very complex meat-bags that change over time, especially so in collaboration with others, so for anyone who feels like trying out the "Camp A" and "Camp B" advice when resolving conflicts in your workplace or when putting together managerial strategy, I'd implore you to maybe think again and tread a bit more carefully.