What is the “average” layout and how do you know what so many different modelers operational “needs” are?
My layout when complete will have stagging for 20 trains each one 35 freight cars or more, most pulled by 3-4 unit diesels or double headed steam. 20 x 3 = 60. Then half of the schedules include divisional power changes. 30 + 60 = 90 locos plus switchers, etc. I barely have enough locos right now to impliment the whole thing at slightly over 100 locos right now.
“the rest” might also be sitting in an engine terminal on the layout to create a realistic scene - right before that train pulls in that needs its power switched/serviced.
I know some loco “collectors”, but I also know many modelers who have very few locos beyond the scope or needs of their layouts. In my circle of modeling friends the “collectors” are a minority.
AND, if someone makes a nice modern 4-6-0, a nice Atlantic and a nice Pacific, I will be pretty much done buying locos.
Sheldon