I can see what you mean, but here is a technical answer!
All vehicles sold in the US have to be OBD2 compliant, your T1N is OBD2 compliant:
http://en.wikipedia.org/wiki/On-board_diagnostics
OBD2 only really covers emissions related stuff (other stuff is non-mandatory)
Most things above and beyond emissions is manufacturer extension to OBD2, there is no de-facto standard that all manufacturers use or that any generic scan tool can assume for anything beyond what is in the OBD2 standard.
And yes, I know some of the OBD2 mandated stuff varies slightly in regard to interpretation for a given engine/system but that is usually easy enough to work out.
So strictly speaking, a vehicle is OBD2 compliant if it meets the mandatory requirements but not the optional stuff, so even where there is a standard OBD2 code that isn't mandatory, the manufacturer complies even if they assign a different meaning to it, or use a different code for the same meaning.... OBD2 compliance in itself does not mean any OBD2 code reader can interpret all the codes!
It makes no sense for manufacturers in a world where IP is valuable to allow all their codes to be understood by any device other than the one they sell!
If I recall Dennis' post the other day right, Toyota data is pretty much out in the open but they seem to be alone....
Most other manufacturers protect their dealer network's market edge with ability to diagnose their vehicles in a way few others can afford to!
I share your frustration, but I can't see the situation changing any time soon!