Why do passkeys often fail to replace passwords quickly?

Why This Matters for Security Teams

Passkeys are often framed as a simple password replacement, but the real issue is migration complexity across identity, application, and support layers. Security teams have to preserve legacy authentication paths, handle recovery and device loss, and prove that the new flow actually reduces risk instead of adding confusion. Current guidance from NIST Cybersecurity Framework 2.0 still points teams toward governance, lifecycle management, and continuous improvement rather than a single technical control.

The result is that passkeys rarely land as a clean switch. They are introduced where the architecture can tolerate them, then expanded slowly as application owners, help desk teams, and IAM specialists catch up. That is why users may be ready before the programme is. The broader pattern also appears in NHIMG research on credential abuse and secret exposure, including the DeepSeek breach, where exposed access paths created outsized downstream risk.

In practice, many security teams discover authentication debt only after they have already committed to a partial rollout rather than through a planned identity redesign.

How It Works in Practice

Most organisations do not replace passwords in one move. They add passkeys to specific journeys first, usually consumer-facing sign-in, high-value admin access, or mobile-heavy workflows, while leaving password fallback in place for unsupported browsers, older devices, and recovery cases. That keeps service continuity but dilutes the security gain because password paths remain available and often become the easiest route for attackers.

Implementation usually requires coordinated changes across registration, recovery, policy, and support tooling. Teams need to decide whether passkeys are mandatory, optional, or conditional; whether device-bound keys are acceptable; and how to handle account recovery without reintroducing weak verification. The NIST guidance in NIST Cybersecurity Framework 2.0 is useful here because it forces attention on risk treatment, not just technology adoption. For identity-specific lessons, the DeepSeek breach is a reminder that exposed credentials and weak workflow boundaries still create real operational damage even when better controls exist on paper.

• Keep password fallback only where there is a documented business or device constraint.
• Make recovery flows stronger than the credential being replaced, not weaker.
• Measure success by phishing resistance, help desk reduction, and enrolment coverage, not just login volume.
• Align rollout with application modernisation, because authentication changes fail when downstream apps still assume passwords.

These controls tend to break down in mixed estate environments where federated identity, legacy SSO, and unmanaged endpoints all depend on different fallback behaviours.

Common Variations and Edge Cases

Tighter authentication control often increases support load, user friction, and integration work, so organisations have to balance stronger assurance against adoption speed. That tradeoff is why best practice is still evolving rather than fully settled.

One common exception is regulated or high-risk access, where passkeys may be introduced first for privileged users and then extended outward. Another is BYOD or contractor access, where device attestation, policy enforcement, and recovery assurance may be harder to standardise. In those cases, passkeys improve resilience only if they are paired with strong session controls and clear fallback governance.

Another edge case is when passkeys are treated as a cosmetic front-end change. If the backend still allows weak recovery, shared accounts, or broad RBAC exceptions, the organisation has changed the sign-in method but not the identity risk model. NIST CSF 2.0 and the lessons surfaced in DeepSeek breach both point to the same operational reality: control strength depends on the full lifecycle, not the login prompt alone. Where rollback paths are numerous and app owners resist change, passkey adoption stalls because the exception handling becomes more complex than the password it was meant to replace.

Related resources from NHI Mgmt Group

• Why do traditional passwords and manual checks fail in healthcare identity workflows?
• Should organisations replace passwords everywhere with passkeys immediately?
• Why do SaaS sharing controls fail so often?
• Why do access reviews often fail in large organisations?