Do people really believe that most startup metrics improve over time?

Is this really conventional wisdom? If so, I’m mindblown by how I didn’t realize I was holding a contrarian position for so such a long period of time during which I’ve met with tons of entrepreneurs:

Conventional wisdom suggests that the most important metrics for a startup – such as unit economics, cost of acquisition, lifetime value, churn rates – typically get better with time.

via Seeing Both Sides: Why Metrics Get Worse With Scale.