Why are steam locomotives what everyone thinks of when they think of a train, even long after being replaced with diesels and electrics?
Probably the same reason that the few remaining steam locomotives are still being maintained and more renovated - they are iconic. https://www.railadvent.co.uk/2018/02/nrm-make-riley-son-offer-for-steam-locomotive-60103-flying-scotsman.html As "Dimo" says about vintage luxury cars vs. new ones, there is something about machines built so long ago (anything up to 100 years for some steam locomotives), a kind of classiness, that's now just not seen.
Steam locomotives in operation get your attention with all that noise, smoke, steam, whistles and driving rod action. Diesels and electrics are kind of dull and their horns sound like flatulence.
Don't be ridiculous,. there are over 7 billion people on the planet so you obviously don't actually know EVERYONE or what they think. I'll bet you don't even know a hundred people by name
Why do people think the 7.4 liter V-16 1933 Cadillac is real luxury car, and the 80 year younger 2.0 liter I-4 2013 Cadillac is not. Answer: Class matters.