There's a middle-ground between job-hopping and unswerving company loyalty: being strategic about your career. Stay in the same place as long as you continue to have opportunities to learn & grow, supportive management, and mission-alignment with the organization. Leave when your career goals no longer align with the needs of the organization. That way you give potential employers the signal that you're interested in new challenges, added responsibility, and delivering value to the organization, but you also show that you're proactive and won't put up with bullshit.
Great article. I've struggled with this for my entire career. I get bored after finishing a major project and am left with miscellaneous tasks. But I've found consulting gigs to be elusive and companies seem reluctant to hire contractors. Even startups. So I risk being labeled a job hopper...
Consulting gigs, particularly good ones, seem easier to get for people who have built a network. People want to hire a consultant who is a proven entity, often referred by a first or secondhand contact. Referrals are really key unless you are interested in the lowest hanging fruit of gigs.