I don't know about Microsoft's policies, but I know that Sony don't force their teams to do anything they don't want to do, and that shouldn't change for a peripheral. Sony provides the money and the developers get to knock themselves out with whatever they want to do. So Sony 1st party developers adopting the Move and 3D is purely of their own choice.
And how are Microsoft not putting their top developers on Kinect? Microsoft only owns Lionhead and Rare, and they are pretty busy with Kinect games (with only Fable 3 being the big game from them that doesn't require Kinect).
And anyway, at this point in the generation, Move and Kinect could never be anything but peripherals. If anything, Sony and Microsoft might be softening the blow so to speak, if they're planning to release their next generation of consoles with control schemes derived from Move and Kinect.
I think the reason so much of their core audiences are hostile towards motion gaming is because they percieve it to be about mini games and waggle. Sony are actually doing something about this, with games like Heavy Rain, SOCOM 4, Killzone 3, RE5:Gold and others; games for their core audience, enhanced with motion controls (though I suppose time will tell if it's really an enhancement). Sony's hardware might seem close to that of the Wii, but they're trying to distance themselves from the Wii through the software, unlike Microsoft, who have very different hardware but the software seems more like your stereotypical Wii game.
Regardless of the outcome this generation, I expect motion controls are here to stay, for all three companies, and I expect the next generation of consoles to launch with some sort of motion control schemes. Sony and Microsoft will certainly be mindful of their core audience and their "needs" though, so I wouldn't be surprised to see something like the fabled break-apart controller from Sony and Microsoft launching with both Kinect and a traditional control pad out of the box.
Okay, if Microsoft only owns Rare and Lionhead, then those are by default their top development teams. This means I have to correct my point: Microsoft doesn't have top developers by industry standards working on Kinect games. Rare is long past its prime and the more talented people of Lionhead are working on Fable 3.
I don't think the hostility comes from the wrong perception that motion controls are just for minigames and waggle, it always had more to do with motion controls being associated with Nintendo. The Wii has FPS games as well as Resident Evil 4 which is very similar to RE5, so I don't think this part of your argument holds water. Also, some of Sony's core audience are willing to embrace/try out motion controls now that they aren't "Nintendo" anymore. We've seen minds changing as soon as Sony showed off their prototype at E3 2009.
Other than that, I mostly agree with what you said.