Analogies to HO and other scales aren't all that informative. There have always been many providers of HO locomotives (same for N). In O gauge, there have never been more than two major players at any time. K-Line, Weaver, 3rd Rail all signed up to use Lionel's command system because there was no other option. MTH chose to develop their own system. Now there is one major player left and they have decided to stop making the cab 2/command base combination, presumably for multiple reasons. One reason is because any device of this sort is subject to obsolescence. Try running current software using MacOS9 or Windows XP on a 2002 machine. Another is the costs of modification to use currently available components, which the main reason Lionel has offered.
When TMCC was introduced in the mid-1990s, conventional operators and long-time Lionel collectors were unhappy in many instances. Change is unpleasant. Mike Wolf (you remember him?) said there was no need for command control, and then changed his mind. People still complain that you cannot get a manual transmission on almost any automobile made today. So it goes, to quote Kurt Vonnegut.
