I've contributed to or led design system initiatives at 3 companies and watched them fail at 4 others. Here's what I've learned about why they fail.

**The common narrative**

"Our design system failed because we didn't have enough resources / buy-in / dedicated team / documentation." These are symptoms, not causes.

**The real reason: adoption is a product problem**

Most design system teams treat the system as infrastructure and are surprised when nobody uses it. Your design system is a product. Its users are designers and engineers. If those users don't adopt it, the system has failed — regardless of how technically excellent it is.

**The adoption problem in practice**

I surveyed teams at 4 companies with mature design systems. In all 4 cases, more than 40% of new UI built by engineers had no design system components. Why? Discoverability (couldn't find the right component), fit (component didn't quite fit the use case), and trust (wasn't sure the component was up to date).

**What actually drives adoption**

Speed: using the design system must be faster than not using it. It rarely is in early days. This is the primary adoption barrier. Trust: every component must be production-ready, well-documented, and actively maintained. If engineers find one broken component, they stop trusting all of them. Distribution: your system needs to be where engineers work, in their IDE, not buried in a Figma file.

**The governance model problem**

Most design systems are too prescriptive. Designers stop using it because it constrains their work. Build with 20% flexibility built in. Not everything needs to be a component.