I had a pretty ridiculous amount of HO trains that I wound up selling off and putting into pinball machines. I still love seeing peoples work, but I fell out of love with the social element of the hobby. I know they say Pinball people have their qualms, but some of the model train folks are downright abrasive and negative 24-7. I learned a lesson in making sure you keep doing your own thing for your own enjoyment, and don't listen to the constant barrage of negative Nancy types that seem to be in abundance. I would imagine some day I will possibly pick it up again...we are in a golden age of model railroading at the moment, with unbelievable levels of factory detail and prototype accuracy. Looking at where the hobby has gone in the last 30-40 years is pretty awe inspiring to say the least!

This right here...I learned so much from my other past hobbies that have transferred over to pinball.

I've never gotten into it, but it seems armor plastic models have a very strong following. There are some really amazing plastic kits from every era and army you can think of. I also hear that the comic/anime plastic models are getting popular as well. Then there are some super niche radio control earth based modelers. These guys build radio control semi trucks and earth movers, and they have events where they have mini cities set up to drive around and move dirt around in. This is far more popular in Europe and Australia though. I do dabble a bit in RC as well...I have a rock crawler bronco that is fun to take out in the woods and trail run/rock crawl with it.

Also, check out the scale modeling thread...I do not want to derail this awesome Model Railroading one.
https://pinside.com/pinball/forum/topic/any-scale-model-builders-here