Except that isn't how it's done. System-on-a-chip means you take the designs from multiple ICs and integrate them on the same die, designing in your own glue to make it all work together.
They are, except that they're not. One is GSM, you got that part right, but so is the other. The 7600 covers all of the 7200's air interfaces and adds CDMA2K in 1x and EV-DO flavors and, since you're so obsessed with antiquity, IS-95. At also adds an audio CODEC or two, a couple of additional AGPS protocols, a number of camera features like image stabilization and adaptive lighting. All of that falls under the "chipset" heading.
I won't argue that the application CPUs are any different, because they aren't. (Or at least not beyond the small incremental improvements ARM made in the designs they licensed to Qualcomm.) They're both 528 MHz ARM11s with an ARM9 on the side doing modem duty.
What you've been trying to prove by assertion all this time is that when Verizon commissioned HTC to build the Eris, HTC sent Qualcomm a purchase order for a boxcar of whatever old CPUs they had gathering dust in the back of the warehouse, and that simply isn't the case.
I sorta feel bad doing this here 'cause it's kind of off-topic, and I actually have something on-topic to say. Could we get a show of hands for who thinks we should have a separate "Enlighten ArtificialSweetener" thread and ask the mods to sweep all of this crap into it?
--Mark