For me, that's where it gets interesting: as I understand, it is perfectly legal for Google to provide services to children, but they must obtain parental consent, first [1]. The problem is that isn't something they're interested in doing.
That's only telling part of the story, as far as I understand. Lightspeed wants the FCC to change their license for (lower powered) satellite communication to allow them to use the spectrum for (higher powered) terrestrial use.
Users of adjacent spectrum designed their products properly for being adjacent to lower powered satellite signals. They weren't designed to filter out the much higher power terrestrial signals that Lightspeed is vying for.
The FCC is not denying Lightspeed the use of their licensed spectrum; they are not letting Lightspeed redefine their license to be something different than it is.
I would also love to see SIP connectivity for Google Voice. That said, the discussion seems to center around the if, and not the why. I suspect that the reason that Google hasn't offered SIP support already is regulatory:
Some time ago, AT&T accused Google of violating telecom regulations by blocking access to certain high cost numbers[1]. Google was able to defend against the accusation by pointing out that they did not actually provide a telecom service, as usage of Google Voice required a normal phone line[2].
I suspect that if (once?) Google provides SIP support, this distinction can no longer be made. What would be the difference between Google Voice and any other SIP provider?