Why Swansea, Mytupi, and Helvetica can co-exist

You see it all the time. There's a Monotype version of Helvetica and a Linotype version. There's a URW version of Balloon and a Letraset version. There's a Monotype version of Trade Gothic and a Bitstream version. Why is this? It never looks like anything's been changed. If it has, it's so infinitessimal that you can't tell the difference without computer software. In the United States (a.k.a Planet Earth's ministry for de-evolution) there is a little blurb in the Copyright act that makes font liberation possible.

In a computer display font, only the source code can be protected under US copyright laws. The abstract letterforms are uncopyrightable.

Even though the entire institution of copyright is in serious need of a major revision, there are still little places like that where people can snake through the chaos.
In effect (if I had the right software) I could copy the letterforms from GE Inspira into a seperate TTF file, call it something (like maybe "EcoLogic NBP") and then I could release it into the public domain. Depending on how many boobytraps GE comissioned, I might have to redraw the entire typeface. But the point is that unless the monkeymen in business suits are hell-bent on proving that "EcoLogic NBP" is an infringement on Inspira's copyright.... more likely than anything is that it would just slip by unnoticed and work its way into publishing houses all across america as a free and highly legible typeface.