Can a subscription-only app truly sustain long-term revenue?

We’re building a subscription-based app, and I keep asking myself:

Can a product survive long-term on recurring memberships alone?

In theory, subscriptions sound perfect — predictable revenue, LTV growth, compounding effect.
But in reality:

• CAC keeps rising

• Churn is brutal

• Users hesitate before committing

For founders here building subscription apps:

Are you profitable (or growing) purely from subscriptions?

Or did you eventually add other revenue streams?

If yes, what worked best for you?

• One-time lifetime deals?

• Add-on purchases?

• Tiered plans?

• B2B / enterprise pivot?

• Community / upsells?

Would really appreciate real numbers or lessons learned.

Trying to understand what actually works in today’s market.