I'll toss in my two cents....
I'm 41. I grew up in Kansas in a small town a few blocks from a Santa Fe branch line between Topeka and Kansas City and a few miles from the Union Pacific mainline through that part of the country.
My Dad always liked trains and consequently, started taking me to watch trains near those lines when I was young. I mostly remember summer evenings. We'd pile into dad's old '66 Chevy truck and drive up north to the tracks. That Union Pacific line was so busy, you could go almost any time of day, wait 15 or 20 minutes and see a train. I got where I was asking him to drive me up there every time I could.
I remember one vacation we drove to Colorado and we road the Durango & Silverton narrow gauge. I still remember that trip distinctly.
My oldest sister had an O scale Lionel train that usually only came out around Christmas time because we didn't have room for a permanent layout in a 700 sq. ft. house with 3 kids and no basement or garage.
Eventually, my sisters moved out, and in the early 80s I found a HO scale Tyco train set with my name on it under our tree one Christmas morning. I put that on a half sheet of plywood and set it up in the spare room. I never got into scenery or anything more than an oval. But I ran it a lot, played with it and my Hot Wheels cars and had a good time with all kinds of crazy imaginary scenarios in my head.
Then, in the mid-80s I got my first computer and the train set mostly sat. Then high school and girls and college and work and girls got in the way. Then marriage, a house, more job stuff, a move, another house, divorce, you know the usual stuff, a.k.a. life.
Today, I am still interested in trains. I work in downtown Chicago and live in the suburbs. I take a Metra train into downtown nearly every day. It's safe, comfortable and keeps me sane. If I had to drive downtown every day, I would either be living much closer to downtown, or I would not be working where I am. I've also taken Amtrak back and forth between Chicago and Kansas City a few times. It too, in my experience has been clean and comfortable.
My dad and I have been to the Illinois Railway Museum in Union, IL several times, and I always enjoy it. We also visited the National Railroad Museum in Green Bay, WI this past summer. I think places like these, operating railroad museums are the future of generating interest in steam and old railroad equipment.
Earlier this year, I decided to take up model railroading as a hobby. I have acquired several pieces of rolling stock and some engines. I enjoy it, but I hesitate to call myself a model railroader. I don't yet have a permanent layout set up and in fact, I have yet to even come up with a track plan that meets my desires and fits into the relatively small space I have available. So at this point, maybe I'm more of an interested observer than an active model railroading hobbyist.
My other issue is that my timing for selecting a new hobby could not have been worse. My wife and I are starting a family and are expecting our first child just after Christmas. My suspicion is, that the next few years, at minimum, will likely not provide a lot of time (and perhaps not much spare money either) for my newly chosen hobby.
As a general observation, it seems to me that most people in the 20-50 age range are too busy working to make ends meet and raising their families to have much time left over for a hobby like model railroading. It appears to me that most of the most active people on this board are in the 50+ range and have finished or mostly finished raising their families, many have retired and as a result they have time, money and space for this hobby.
I do have a concern that over time, because trains are less important (maybe less visible is more accurate) to the average person that there will be less interest around model trains. I certainly think that the death of the LHS will be detrimental to the hobby as well as it prevents those impulse purchases of trains and train sets.
All that said, I absolutely do plan to take my daughter to places like the Illinois Railway Museum as well as take her for rides on Metra, maybe Amtrak and she may even get her own train set at some point, or maybe she'll just get to play with daddy's train set.
But do I really expect her to become a future model railroader, no, not particularly. Time will tell though.