Yeah, the economics for a SaaS application are in some ways very different than a supermarket. I imagine that many of the products that eventually get cut are still "profitable" in the narrow sense that each unit sold is sold at some margin above cost. But when you take into account the enormous opportunity cost of stocking that item and taking up shelf space for it that then cannot be used for something else that moves at greater volume, it becomes uneconomical.
A SaaS app doesn't have the same sort of physical opportunity cost -- every dollar earned is a good dollar. The only real opportunity cost involved is the creator/employees' time.
I want to take issue with "Every dollar earned is a good dollar" at essay length. It's widely believed to be true by devs starting SaaS companies and sometimes dooms good people/products by e.g. makin them scramble to find 50 $20 a month accounts when they'd sleepwalk to 3 $10k a month ones.
I normally like your comments, but I believe the OP addressed this. They said the opportunity cost is the creator's time, which I believe takes into account your objection.
(Of course, responding to the a standalone phrase, you're absolutely correct)
Providing support has an opportunity cost as does developing features requested by users. If your early users are "harbingers of doom" and you listen to them for feature requests, you're going to have a rough time.
Recently I signed up to test a new SaaS app that I thought would be useful. The marketing language on the site was a bit different from what I found inside the app once I got going. I asked the support team for help and instead of leading me on with promises of adding things in the future, they just told me the app was a bad fit and refunded my money. I appreciated that. I was not going to be a productive user for them. Focus is key.
I think this is one of the reasons apps like Stripe take so long to go international. The user needs are very different and there's a real cost to taking on the responsibility of grappling with them.
A SaaS app doesn't have the same sort of physical opportunity cost -- every dollar earned is a good dollar. The only real opportunity cost involved is the creator/employees' time.