At the moment apps have no future: Money from apps was during the days app stores zinaanza, people were likely to be millionaires because the market was still new: but at the moment the likely hood of you making it to the store is very low unless you can make people to have attention on your app, before flutter you can make android, ios apps with google chrome itself you dont need to code any backend language as you have a website already: we should look forward into new tech advacements such as internet of things, artificial intelligence and many more