Technically Netflix, Spotify, etc. are content as a service, not software as a service. The software serves to provide content - if there was no content the value would be gone.
Marketplaces are abundant, Amazon is worth a gajillion dollars.
There are probably a multitude of non-profit tech companies that work off of donations and 0 interest funding.
OpenAPI sells credits based on usage.
Also do we need another business model, financial model, etc.?
… good luck.
My IMMEDIATE concern is a legal and ethical one.
A certified dietician undergoes many years of study to develop diet plans specific to individuals. This involves taking into account not only goals, but body weight, BF%, pre-existing conditions, family history, etc.
ChatGPT is not a certified dietician and your app does not provide expert advice. I would be very careful with an application that auto-suggests diet plans for someone. If it suggests a diet plan for someone which causes health issues or worse, death, that’s on you and your brother.
I’m a qualified personal trainer; if I client asked for a diet plan I would state the following:
Obviously I’m just a dude on the internet, but people’s health isn’t something to be messed around with. Could you go to sleep knowing you’ve seriously hurt/killed some of your users?