How to calculate and reduce payback period

Paylocity: have a network of over 30,000 brokers and generate ~30%+ of their ARR through referrals.
Shopify: acquire most customers organically (~40% by word of mouth at their IPO and 30% through partner referrals).
Atlassian: mostly sell directly to technical users, who collaborate on product development, with a low-friction, self-serve sales model.
Veeva: took first-mover advantage by creating a bespoke CRM for pharma and biotech reps.

If you pay for a cup of coffee, you enjoy the warmth and taste in the moment and benefit from the caffeine kick a few hours later. If you pay for health insurance, you benefit from it two years later when you need your routine exam. If you pay for a customer, you don't benefit from the acquisition until the customer's subscription revenue exceeds their cost of acquisition.