Yes, John's response is a very enlightening and well written synopsis of the issues facing railroads.
I have spent far too much time depressed over the state of railroad demise, as if every lost line was lost forever. It wasn't until I started to learn more about the history of railroading (especially in the U.S.) that I began to realize the overwhelmingly tumultuous past of the entire industry. There has never been a time when railroad magnates weren't squabbling over rights of expansion, even to the point that they were trying to out-compete one another on opposite sides of the river, or pay off landowners to be hostile to selling access to the other railroads. Constant change to lines, abandonment of unprofitable track, mergers and dissolution has been a constant factor that makes the story fascinating.
Nothing abandoned is abandoned forever. It remains an asset that can be recycled when it becomes profitable to do so. And considering the amount of clutter in the U.S. when compared to Eastern Europe and Russia...
I've done the same and gone as far as getting that awful pit in my stomach when I've come across an abandoned rail line, which at one point I too deemed should never have been removed. In some cases yes, especially after Guilford and Conrail did their slashing and burning of the rail landscape. In other cases, well there are some line which only served a single industry such as the lumber industry, for example. Those lines lasted as long as the industry did that supported them. New Hampshire's White Mountains are covered with former logging roads [sic], I mean railroad ROW. One of the lines, that has landed on my someday list, was about 78 miles long and covered the Pemmigawasset River side of the White Mountains. There's only a short stub left today that's used by the Hobo Railroad in Lincoln NH, and there's a stuffed Shay sitting next to the Kangamangus Highway as it enters in to Lincoln. The rest disappeared over time and lost regular freight service in 1980s when Guilford pulled out of that part of New Hampshire and the line is owned by New Hampshire government. They also did let the Concord to White River Jct. mainline go then as well. Today that's a snowmobile trail and at one point there was discussions about bringing that back for passenger use, but New Hampshire is as anti-rail and pro-highway as they come.
Speaking of competing lines, etc. In my local area the Boston and Maine as we know it started as multiple small companies such as the Andover and Wilmington (ca 1830), the Haverhill and Andover, the Exeter and Haverhill, the Exeter an Portland, etc. They had to contend with the other state-chartered and supported railroad the Boston and Lowell, which ran between the respective cities. In order to continue to Boston, they had to wait for permission to enter the B&L. In the late 1840s the B&M rebuilt its mainline to what it is today through Andover, and also built its own mainline via Reading and Wakefield on to Boston. The B&L brought them to court because they had an exclusive charter to run the trains into Boston, and the ensuing court battle ended up in favor of the B&M, which by the late 1880s owned them anyway along with most other lines in the region including the Boston, Concord, and Montreal, Lawrence, and Lowell, Manchester and Lawrence, the famous Eastern Railroad, and many, many others.
After their peak in the early 1910s, they became a proxy to wealthy stock holders who used the railroads as pawns for profiteering. (Sounds familiar). As industry declined, the railroads did as well. Branches soldiered on as needed, but when the Depression hit, many were cut up and sold off. The Essex Railroad, for example, that ran between South Lawrence (North Andover line) to Salem via Peabody and Danvers, was cut up and sold for scrap. The metal was used for the War effort in WWII. The Essex RR was never particularly profitable even from the beginning, and was bankrupt before it was purchased by the B&M.
Other lines were direct competitors such as the Eastern Railroad. This line served the seacoast and ran nearly flat and straight from Boston up to Portland Maine. Built in the late 1830s to early 1840s, they did quite well, but had to rely on a ferry to come in from East Boston. When the new North Station was built, the lines were consolidated and they used trackage rights to enter into Boston as well as a then recently built line in Everett which connected to the B&M mainline from Reading. In the 1880s, they too became part of the B&M, and became a mostly commuter line. Their through service ended in the 1930s and big hunks are abandoned today. The Worcester, Nashua, Rochester & Portland met the same fate in the 1920s during the tough times. The route did host the famous potato trains and through passenger trains from NYC to the White Mountains, but that route competed muchly with the B&M's western division and Fitchburg Railroads. When push came to shove, the more meandering WRN&P was mostly pulled up. There are a few small segments still around.
The list goes on.... In some cases lines were built by one company just to encroach into another's territory. The B&M did that with the Lawrence and Lowell. That line was used to siphon off lucrative mill business in Lowell and send it via Lawrence and down the B&M mainline to Boston via Reading. The line was supposed to run along the Merrimack River, but ended up veering inland and running via Tewksbury because some major stockholders wanted a rail route. The line was severed in the 1950s and 60s when I-495 was built with the two end portions being used for freight. Today the South Lawrence end is operational to an industrial park. The Tewksbury side was abandoned because Guilford, at the time, didn't want to serve the few remaining industries at that end.
The railroads, like any business, are all about money, profits and money, and did what they could with their toys then what is done today just the same with other medium. This was Railroad Tycoon in the real world.