This is a very interesting topic.
Model railroads are odd in that they contain a lot of little details, fragile things, etc. They’re unlike most things in our houses / garages. Most other things can be vacuumed, washed, etc., and don’t have tons of moving parts.
I almost think that model railroads are on a continuous decline from day one. You build it, then things start to deteriorate.
One of the worst offenders seems to be scenery. It gets dusty/dirty, and how could you really control that? You could try to slow the process, but you’re only slowing it down.
I grew up as a kid seeing a huge 2-rail O-gauge layout at the LA county fair. It was huge. The equipment running on it was beautiful. But there was no denying it was on a constant decline over the years. The scenery, etc. was aging, and that’s just a fact. They layout was there for like 50 years or something before being removed (still makes me sad).
I’ve been getting back into the hobby by learning to handlay track and turnouts. I have a couple scratchbuilt turnouts in the garage, and I kid you not, when they are a couple days old, they’re dusty already.
Here is an interesting concept: Garden Railroading. With garden railroading, the scenery is alive. You have to continually work on it, but it doesn’t get “old”.
My plan is to have a couple modules for an HO layout, with a return loop or something. The idea would be the modules would be covered in sort of a shadow-box to keep the dust minimized, could be taken outside for photography, etc.
I personally have abandoned the concept of a layout being a way to model a “railroad”. For me, model railroading is all about the “stage” concept - mentioned in MR years ago, where the layout is merely a “snapshot” of a railroad line. Basically, a small scene where the trains come in on one side, and exit the other side.&