Sideloading is not accessible to everyone, even though it's fairly easy to achieve. Most users, even technical, would not want to rely on such methods for installing a development environment (or customising their devices for example); Any tentative for monetising an application that depends on sideloading would be bound to fail at scale.
Is the context I described responsible for the lack of market? It may be.
I still think that iOS is the best mobile experience out there, but it's
There is almost nothing stopping people from writing up iPad apps for coding things up, except for the fact that there is no market. Apple is no longer standing in the way IMO (stuff like Pythonista exists after all)