I've heard this phrase (and variations of it) countless times from veterans in career transition.
Its no BS. Our veterans are some of the most, agile, adaptable, development-focused people on earth! They are highly capable and have seemingly endless desire and ability to grow their capabilities.
But 'capability' is not enough in career transition.
To land that great new gig you must be 'credible'. To keep that great role and grow your career over time you must continually expand both your capability and your credibility.
Employers hire (and retain/promote) the people they are convinced can 1) do the work they need done and 2) will fit well and add value to the team. They hire people they believe are 'credible' in their world; people that have built a level of trust with them; people in whom they believe.
Remember, in the transition game making yourself 'credible' is a capability you need to 'get smart on'.
If you'd like to learn more, give me a shout!