A recent Nationwide commercial has former NFL star Peyton Manning walking within Peytonville, a town set up on a large layout in a warehouse:

What makes attending such layouts attractive to people? Three quick guesses:

1. The ability to craft and build an entire community. In real life, no one person could do this on their own. Even a fabulously wealthy person would likely have to rely on a lot of help – think construction workers and others – to put a community together. This sort of layout is possible with a lot of time, materials, and skill (particularly given the size of it all).
2. The birds-eye/God-like view (and control in #1) possible with such a layout. It is one thing to walk within an interesting place; it is another to consider it from above.
3. The chance to attach one’s name to a community. This is an honor often given to a founder or a prominent early member of the community. If you control the construction and have a birds-eye view, you can add your own name to it all. The community in the commercial is Peytonville but it could be Peytonton, Peyton Corner, Peyton Park, and other variations.

It would take a long time to put this together but it could be very fun to maintain, play with, and show off to others.