Good point. I would argue that timing of payments makes a big difference if you have high costs on the units you sell, e.g. EasyPost with shipping labels via API request. But for other SaaS with high margins you would only front very limited money for like 30 days.
Couple of counter-measures for this exact point I have seen in the wild:
- companies letting you top up your account balance, then do usage based charges on the balance
- companies having a billing-threshold where they trigger a payment (or multiple) during the month