Sorry, but at this point you have no idea what the maintenance looks like.
I've heard this argument a few times on here, I think it's nonsense.
At 30 users you have no idea what maintenance looks like. That's literally what maintenance is - responding to real world usage.
Come back with your experience when you have lots of users that stick with your app, you're putting out fires and implementing new features. Your experience will be meaningful after 6 months to a year.
I'll wager that right now you have a PoC that needs a lot of work to be something that retains users. That's not a criticism, that's just how it works for every startup.
I have a pretty good idea about what maintenance looks like. Particularly so about the technical aspects of how effective the models are at refactoring or fixing bugs.
Even if I were to accept the argument that users would have entirely different expectations for my app than I do, it hardly changes the fact that I already know I can easily implement large changes in the code base.
Come back after running your mobile app for at least 6 months in the real world with real users and then we will talk about maintenance.
I'm still in the process of launching the app, it went live just two weeks ago. So far only 30 users, I have not yet started the ad campaign.
Basically I don't look at the codebase at all, I have long stopped using the IDE or doing code reviews.
From a product perspective, there have been no big surprises. Only once I was surprised to see a feature I thought I implemented only on a specific screen being available on a different screen too, hidden behind a drag gesture, spawning an UI component I totally did not expect.
While that seems like a loss of control, it's not too different from enterprise work with many contributors where I am also not aware of all changes.
About maintenance cost, no, I do not think so. It generally became easier over time since Opus 5.5 delivers better results than GPT-5.5 did.
From a token perspective, a large part of the resources go into translating to 30 languages and checking the screenshots for layout regressions.