I'm on the hunt to build such thing (https://tablam.org + "excel" + "access OR fox pro", ...) and I have never consider the "all in one" a paradigm for end-users.

As you discovered, is for you as the tool maker and for your power users. On top of that, let's say you make "widgets" or "mini apps" that are built on top.

ie: You make Django, but you ship: Shopping cart, Blog, Wiki, each with their own UI and App branding