Funnel metrics tend to decline with each successive cohorts as a company grows and saturates segments that have strong product market fit. On closer inspection of retention, this reveals adjacent users (not the power users or what you think of as the primary user persona) who struggle to adopt or continue using your product.
Adjacent users have different needs and present opportunities to unlock new audiences. For example, Instagram noticed many international users logging out or using fake email addresses because they prefer text messages, use pre-paid internet cards, and were worried about using bandwidth. They made it easier to log back in (rather than harder to log out) which helped them better retain international users.
To acquire more adjacent users, one should also consider the sequencing of which user so that it’s additive and makes it easier to get other adjacent users.