So the value of the routes is only it's scenarios? Not the time and effort gone into building the route, not the length of the route, not the rolling stock (if any) supplied with the route. Just the amount of scenarios, hmmm seems I need to rethink why I purchased well over a grands worth of DLC then..
The B&O Mountain Subdivision: Cumberland - Grafton Route is a 1.6 GB download where most other routes are about 800 MB download and you still get a 1.6 GB route for the same price as an 800 MB route. Speaks for itself. I think the developers of this route, not DTG spent a year doing this with 6 people working on it. They have to recoup money from somewhere.
If we only played the scenarios provided then TS would be hugely overpriced. Fortunately you can play quick drives, subscribe to workshop scenarios and create your own scenarios. In fact most routes rarely come with all the associated locos/units (modern PDL is only one I can think of that comes pretty close to having all the stuff you'd need). You'll need to create own routes or subscribe to workshop if you want to play your full range of appropriate locos on a route and have other locos as AI.
