Relay margin is often misunderstood as a simple buy-low, sell-high spread. In reality it also depends on package design, usage mix, failure rate, support cost, risk control, and refund disputes.
The visible price spread is only the easiest layer to notice.
Price spread is fragile
If a relay competes only on price, cheaper competitors can pull it into a race to the bottom.
Healthier margin comes from model mix, peak/off-peak usage, quota design, retry control, and risk filtering.
Stability affects margin
Poor availability creates retries, support tickets, disputes, and churn. Reliability is not just user experience; it is cost control.