In a software business? Presumably the margins per additional customer is 90%+, although with fixed costs it could obviously be much lower overall. But the marginal profit per user is the primary concern here I think with regards to payment provider cuts? As the fixed costs of development are already relatively set whether they have one user or one million.
It’s true, though, if they have a lot of manual support that could certainly hurt that, though. Or if they have a high customer acquisition cost. Excluding fixed costs if they are spending 50% per marginal user on marginal Dev/server costs, support, and customer acquisition, the numbers do start to get pretty uncomfortable. Would have to gain 50% more users to break even relative to the 3.3% cut.