To be forthcoming, the Software Store is not developed by Canonical.
It is developed by the Gnome Foundation. It is the Gnome-Software application.
And Gnome is very well known for doing only what is good for them (generally anything that reduces workload) while utterly ignoring user requests.
On the surface, this looks great. But when you think about it, being Open Source is not exactly a key to the city.
Having Open Source only means that technically you could change an app. It is not so easy...
You must consider the dependencies involved and the conflicts. And then this is applied broadly across all applications of a system. As it is, many people already post threads commenting about the Long Development Period of Zorin OS. Claiming that the LTS version is "massively outdated" (No, it is not) and so on. Increasing development time would only encourage more of this commentary.
And coding is not so easy. Imagine having a job where you must switch between speaking American Sign Language, French, Italian, English, Spanish, German and Russian with each task and within each task. You must also learn-as-you-go all nuances in between, make it concise and dynamic (avoid hard-coding wherever possible).
It becomes a pretty hard-hitting catch-22 or balancing between the time, knowledge and resources available and user expectations.