When is two too many? [standards]

One statement often repeated in the standards world is that one standard is good, but two standards are bad. I´ve heard this statement lately, and take exception with it. I don´t disagree that one standard is usually better than two or more, but that doesn´t necessarily make two or more standards bad. Good examples of multiple standards that work are modem standards. There is the old, reliable 300-bps modem standard. I don´t know about you, but I don´t use it. I use the V.90 56-Kbps standard. In fact, there are many modem standards. If we didn´t have many, we would still be using 300 bps. There are many other examples of multiple standards. But, you may say modem standards aren´t a good example because each improves on the previous one