That makes sense given how they wanted all the lines around them for their own. The old B&M and New Haven did the same back east, but that was during the 1900s and before. The B&M bought up some better running lines and then abandoned them in favor of their own. A good example is the Eastern Railroad, which had literally, not figuratively, a straight as the crow flies route right up the Atlantic Coastline from Boston to Portland Maine. This route is no longer quicker than the more roundabout Western Division, was flat and level, unlike the Western with its 1% grades, and double track all the way to Portland. Instead by 1930 the Eastern was single tracked and ten abandoned mostly after 1957 when McGuiness and his crew were cleaning house for their stock holder buddies. The New Haven wasn't much different and owned nearly everything in Connecticut, all of Rhode Island, parts of New York, and the whole southern part of Massachusetts. They even owned the B&M at one time too, but then they got screwed by the panic of 1910, just after they electrified the Hoosac Tunnel.
The old MILW too, like the ROCK, was run into the ground by their owners and sadly cast off once they couldn't suck another drop of cash out of the old wreck. The SOO getting the old MILW was probably a good thing. I've seen what they have done with their main line through Mobridge, SD and it's quite an amazing difference from what it once was.
I wonder if the UP or even the BNSF is looking at the Cowboy Line as that would definitely mean a quicker route east. It would mean, however, relaying track again and rebuilding any bridges, especially that large one up in Valentine, NE which is right on the border with South Dakota. We stopped at a Micky D's there for lunch and the ROW is still intact, although with a walking path where the tracks should be. It made me sad inside to see this empty ROW with nothing but a few people here and there on a short paved section and the rest nothing more than a dirt path.
John