I assume the instability appeals to them because they can move on before anyone realises what a pig's ear they have made of everything.
Most of the highly competent developers I have worked with have spent 7 or more years in one organisation.
From my anecdotal experience, therefore, tolerance to short-term disruption is negatively correlated to ability. However, I would be reluctant to make any assertion that links potentially unrelated traits like these.
In my (again, anecdotal) experience, organisations with more stable positions have a greater proportion of people who value that stability for its own sake e.g. those with primary care responsibilities (e.g. for children or disabled dependents); those with voluntary commitments (e.g. scout leaders, special constables); and people who have cause to worry about discrimination (e.g. those from demographics that are poorly represented elsewhere in their profession).
That correlation would be one that I would be slightly more comfortable to assert.
My own experience in the public service was not so much of people unable to do their jobs but people unmotivated by them. My welcoming speech included the warning 'don't get attached to outcomes', and this was in a department disliked by the elected party where a lot of people had already been forced into early retirement.
I think it is rarely that extreme. Preference for stability rarely means complete inability to deal with instable situations. Also, let's not overstate instability of average tech job. It is not that bad.
That is seriously odd assumption. It sounds like confusing "personality trait that appeals to me on emotional level" with ability.
Plenty of inable unstable people around as far as I can tell. Plenty of low ability risk takers too.