I think there are two things we're talking about:
1 - a kid oriented environment/playset
2 - collector oriented environment/display
I get it that maybe #1 doesn't have a huge market, but I'm surprised Hasbro/Disney hasn't sub-licensed the collector oriented environment/display, maybe even as a shared exclusive for EE or someplace.
I know there have been a few marginal attempts at this over the years, but as I recall the price points were crazy high (someone refresh my memory on the company and price point - I think they were $100+ and not modular - sort of like nice reproductions of some of the classic mail away displays).
I find it hard to believe that someone couldn't engineer and produce a semi-generic Death Star / Star Destroyer / Blockade Runner / Starkiller Base hallway environments at a reasonable price. I know some 3D printer garage shop guys have done hallway environments, but this needs to be an injection molded higher run product that gets distributed through a professional company. I know I would likely buy a handful of these to act as stands and display environments. How many of us have bought hundreds of Hasbro and non-Hasbro stands to display our figures???
Back in the day Kenner got halfway there with their mail away Arena Display. Something like this concept with some vertical supports that could allow you to stack them and build environments couldn't be that hard to pull off.
I'm sure some kids would buy them too, especially if you were clever about how accessories and other items could plug in to the environment. You could make them a mail away and online shared exclusive. And they could be refreshed with new accessories or inserts with each new movie. For example, it looks like a chunk of Rogue One is taking place inside of Star Destroyers and the Death Star.
This seems like a no-brainer.
Where is EE when you need them? I'm guessing Hasbro just won't let anyone do this.