As an attempt at a definition, the only time you will ever truly own something is as an individual contributor. No one will edit the code out from under you. But as soon as you enter any sort of organizational context, you start to realize that ownership is largely a myth. The more responsibility you have, paradoxically, the more that responsibility is shared with others. From every direction, people will be editing your supposed creations.
That's not a bug - it's just the nature of the thing. As a practical matter, you need to be comfortable with people submitting pull requests against your ideas, and in fact this is part and parcel of growth. Increased responsibility is attended by both a need to drive more, and also to thrive in the shared ownership. The ability to handle this reality is a massive determinant of leadership potential, organizational health, and success as an enterprise. The inability to handle it manifests as stunted growth and pathological distrust.
Even if complete, individual ownership is largely a myth, it's still an exceptionally useful one in terms of understanding organizations and leadership. The traditional model is that you have a defined position with a defined portfolio. If this sounds stifling, it is. Its chief virtues are predictability and legibility- all other things being equal. And this is why conventional, status-driven organizations are so often ruthless and dysfunctional, more than the existence of the hierarchy itself: things change. You can only be really aggressive and formal about promoting leaders if you are equally aggressive about firing leaders. It simply isn't possible that you are always right. This is how most organizations avoid the alluring, yet messy, challenge of decoupling position and portfolio. They become factories, and as they grow, they become fractals of the old org chart.
The alternative model is the artist colony, in which position and portfolio are not only decoupled, but the position itself is an arbitrary construct. There is only the artist and the work. We see this influence in Facebook's engineering teams, where everyone from new grads to eminent veterans gets the title of “Software Engineer”. We've done the same at Palantir - with the added wrinkle that BD is all engineers as well! As a variation on the theme, recall that the Dalai Lama famously describes himself as just a simple monk.
Within the artist colony, there are leaders - and in fact, they are the rule and not the exception. Their portfolios can and will change radically over time. This decoupling allows the colony to seize more aggressively on the innumerable opportunities for leaders to drive things, without creating a corrupting permanence to whatever is being driven. In fact, I would argue that leadership can only be taken in times of flux. Otherwise, it's just more skillful maintenance. The architect of the palace does not mow its lawns, however necessary a task that may be.
The fundamental fluidity of portfolio and position constitutes the artist colony's greatest inherent advantage (and challenge). In a traditional organization, it's expected that taking away a portfolio implies the loss of position, and vice versa. In the artist colony, it's understood that this would end poorly for all, not just the artist in question. Broadly, the result would be creeping risk aversion and status-seeking. And, more often than not in my experience, just around the corner lies the perfect thing for the artist to create - while also meeting an existential business need.
Meeting these needs is not just a happy side effect of individual fulfillment, but a strategic recognition of the nature of progress. It's a constant struggle and dialogue. We need to force ourselves to the front when the things we are driving push us back, but true leaders are not content to blindly take the next hill. Each success creates the imperative to ask “now what?”. At a certain stage, the logical next step might well be an oversight role. But what's much more interesting, to me, is how often I've seen leaders ease their developmental angst and do great things for the company by pivoting from oversight to owning and executing something meaningful.
On a similar note, we're all familiar with stories of leaders not scaling because they couldn't delegate. But we should be more worried about leaders losing their ownership/execution muscle entirely. In many of these cautionary tales, I'd wager that the real takeaway should have been that Leader X didn't own/drive the right things, not that he/she didn't delegate effectively.
Another benefit of decoupling position and portfolio derives from still another paradox: despite the necessity of joint ownership (or perhaps because of it), some things simply require a dictator to get done. This is especially true in product development, where not only does halving the team often double the pace of progress, but the fulfillment of a coherent vision usually requires one actual visionary. Dictatorship as a set position would never work in an artist colony because it's antithetical to the nature of art and artists. But dictatorship can not only work, but thrive, in the context of portfolio.
It should be acknowledged that the artist colony, like the artist, is a fundamentally restless entity, and this approach is not a panacea of any kind. It requires constant engagement and examination, and betrayals of artistic principles within this world will sting infinitely worse, because so much more is at stake than status and money. Owning your work, then, is the opposite of owning your home: it's only true ownership for as long as you're actively paying it off.