My personal take on this is that while, in theory, an enterprise has the right to conduct its business in any form it chooses, including further mega-mergers, to do so would be an invitation to some very unwelcome governmental interference, given the current political climate.
Deregulation, as applied in theory to any field of enterprise, is supposed to bring about greater price competiion as new players enter the market. But the railroads' complete ownership of a right-of-way which is (1) fixed, (2) extremely expensive, and (3, and most important) seldom offers possibility for improvement due to the over-riding importance of ruling grades, implies that competition based on either price or quality of service would be far from uniform due to the inherent advantages or disadvantages of the limited (and declining, due to techological factors) number of suitable routes. (This would not be the case, however, in the large portion of the interior U S which is generally flat, provided the NIMBY syndrome were not allowed to block the revival of some abandonded rights-of-way.)
If some measure of increased competitiveness on a nation-wide basis is ever fostered within the rail industry, it could probably come about only if a model along the lines of practices within the electric utility industry, with service providers sharing facilities, were to come to pass. Unlike the case with electric power, which is a force that might best be likened to steam pressure, the individual units (vehicles) are differentiable, but the current major players would likely surrender their individual propeties only on threat of outright confiscation/extinction.
And unfortnately, I view any number of irrational scenarioes as possible if the general economic and political climate contines to deteriorate.
What a revoltin' development this is! (William Bendix)