Okay, while Myst 2 and 3 were the only ones made by Bungie, let's take a look and analyze it. There was a Myst before there was 2 and 3 (obviously), therefore Bungie jumped in for those two. Thos two got pretty bad reviews, primarily because they didn't expand upon the original Myst enough to make as large an impact. Coincidentally, Bungie pulled out, yet the series continues, with Myst: Revelations, out now for the PC and soon for Mac (I believe though it's only rumors...), and boy did Ubi expand... This lends to the argument that a game's world does NOT come to an end when Bungie leaves. So, I find it VERY unlikely that Bungie and Microsoft will give up on the Halo universe, which MS has been milking for the last couple years...I mean come on, what other game do you know of that was being sold at the original price for more than 6 months, let alone 2 solid years...
And just because Pete Parsons, whoever he may be, says that "they will try to move onto another series of games", doesn't necessarily mean their going to abandon quite possibly the single most popular game they've EVER created. As you said, we are dealing with the almighty Microsoft here.
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