Just my take on Arc...
Sony already had a motion controller 'SixAxis', and they did Nothing with it, ya a game or two, and then some games with a motion notion here and there but that was it.
When Sony first talked about the Sixaxis, they made it seem that many, many, games would have the feature and it would take the place of rumble. Now it's like they want people to forget about it.
You don't really see Sony trying to push the 'Arc' like other companies are pushing their versions, it seems more like they are taking a 'if it works it works, if not o well' approach.
I went to allot of Game stores in my area these past couple days, and majority of the discussion were about new games just released, Natal, DS:XL, Ipad, but nobody even mentioned Arc.
PS3 never really grabbed the 'family/casual' approach with the PS3, people touted about how majority of PS3 owners are adults, just look at the games recently released, nothing really says 'family console', and to me Arc seems to like a Wii approach to gaming, but with an Adult non-casual install base.
This is just my view on Arc
I've said this (underlined) many times, and other users on this forum laughed at me or I got reported for flaming, saying that none of the PS3's games appeal to the general audience and are mostly teen/adult games. Unlike what the PS2 had, Sony lost all of that support when they shot their own foot with the PS3 and lost the developers (mainly giving the shovelware) to the Wii.
And no, I don't think Wii owners will upgrade to the PS3 with the Move controller. Why? It doesn't have the same games that Nintendo has on the Wii that people want.
Still, the Move does seem like a good device, but it's a little too late to release it, and as you mentioned, this should have been at the beginning of the PS3's life.