edit - the microcontroller was called Pico, not Nano
If there's any truth to this rumor it's probably ARM discounting the license fee for the fraction of devices that Broadcom sells to the Raspberry Pi foundation.
ARM knows that RPi is the go-to ARM SBC, and they benefit tremendously when developers treat it as a first-class platform.
Apple pays ARM for an architectural license, just like any other company.
ARM was created as a joint venture between Apple, Acorn and VLSI.
At that point, yes Broadcom is ultimately paying the fees to ARM, but separating RPi from that negotiation is an oversimplification. RPi absolutely has a seat at that table.
And ARM probably doesn't care that much about it being the go to SBC (some cheap chinese board would take on that mantle without RPi leading the charge), but instead that it's the practical successor to what ARM was founded to do. Put passable performance, hackable computers designed by Brits in front of British school children as cheaply as possible.
I ultimately think you're right, and we won't see a V9 in an RPi for a while, but it's a more complex situation than most SoC integrators that has a slight chance of working out in RPi's favor. Does ARM care enough to make a tiny core in their gate count niche? Does ARM want to give the free new cores to increase market share and get V9 features in the hands of tinkerers? etc.