Holacracy is a system, based on a set of principles. It is not the principles — it is the system. To move away from Holacracy means we are changing a system — not our principles.
One way to think about Holacracy is it’s kinda like a software framework. Usually, frameworks take a while to get up to speed with, but once you do, they can add convenience, power, and consistency to how you do things. If chosen well, a framework selected early on can serve your needs inevitably as you scale. (Wordpress is still in PHP, for example.)
Other times, the nature of your application (or organization) starts to chafe against the constructs of the framework. Twitter was first built on Ruby on Rails. Though we moved away from it later, RoR got us to product/market fit. And it’s great for lots of jobs/developers.
One of the cool things about Holacracy is it can be applied to any type of organization. But by their nature, general purpose frameworks often carry with them more overhead than something purpose-built (but more limited in scope). So it’s common when your organization or application grows to trade third-party solutions for home-rolled ones, which are more efficient for your particular use case.
This is what we plan on doing with our organization system. We have some specific ideas about how that will work differently than Holacracy. But the reason we are not very specific about that new system is because it’s fuzzy and evolving as we go. (On a day-to-day basis most Medium teams still run Holacracy-style tactical meetings, as they are totally separate from how you structure — and they work really well.)