Postwar or whatever you want to call it is always going to be out there, it is one of those things where it is up to the people involved. I think modern Lionel (for lack of a better word) is aimed at command control (lionchief/legacy) and most of their rolling stock is scale except for 'fantasy cars'. Expecting new roadnames in traditional size is likely to be an exercise in futility, they are definitely aiming at the scale market. Menards is filling that niche it looks like. For those who like traditional size stuff there is a lot out there (not to mention the conventional classics Lionel had out there until not all that long ago).
For me, most of my stuff is conventional and traditional sized, it is what I had before my hiatus. Once I am up and running, I haven't decided what to do with my conventional engines, whether I'll regularly run them; if I do, then I will convert the ones I want to keep running regularly into command control if at all possible, the others I'll run conventionally (if I can scrape up the money for a zw-l when the time comes, I can run conventional engines using the built in powermaster capability). I am not a purist, I'll likely run what I like and not care scale or traditional sized, but that is me.
Over time I have no doubt that PW will continue to take a back seat to the more modern stuff, but there will always be people who like it, for simplicity or nostalgia (hey, there is something in car culture where young people, with some unique twists, are fascinated with 50's cars and modes of dress, kids who were born in the 80s and 90's...).