"The fact is, most youngsters couldn't care less if the engine is 1950s tooling, or its windshields and number boards are wrong, or whatever; they just see a train,..."
Very well said. I am now in my sixties but many track miles ago, when I was about 10, my uncle gave me a Marx HO set for Christmas. I thought that was the coolest locomotive and set of cars even though it was even more crude than the Athearns! That following summer, I saved my pennies and bought an Athearn flatcar and a dummy Athearn GP9. Never mind that the body on the locomotive was too wide, I thought I had arrived.
In a child's mind that Blue Box loco is heaven sent and what better way for them to start out? Better for the child and better on the parent's pocket book. And don't worry... As they grow older and start to earn their own money, they'll find their way to the pricier items...
As for the Stewarts, I have a set of Bowser Stewart's, Stewart USA's and the Kato drive Stewart's. Can't say enough about the Kato drives; they are tops. The Stewart USA's aren't bad. I bought a set of Northern Pacific Bowser Stewart F9's and I wasn't impressed with the growling that I heard as soon as I put them on the track. Clean up the mold lines on the older shells, add some details such as grabs, etc. and you'll have yourself a nice locomotive. The profiles on the Stewarts are, in my opinion, among the best. There are still a lot of Kato-powered Stewart locomotives out there. Some folks buy them from eBay, others look elsewhere. I employ a lot of Kato-powered Stewarts and Kato-powered Atlas locos as well.
Main Street of the Northwest