Seems like a silly question, there are a huge number of factors that play in on such decsisons.
Not at all!
Assuming MS is indeed going to include HDMI (something I don't really hold for certain at this point), to point out that from going to say that it isn't neccessary to doing a complete 180, is certainly not a silly question.
I don't really see what 'huge' number of factors you're referring to may be. MS knew just as well as Sony that HDMI is the future, not including it from the get-go is certainly nothing short of shortsightedness, and their offered excuse that they'd include it when it makes sense, is just plain lame. HDMI makes perfect sense ALREADY, and definitely even more so in the very near future.
That doesn't concern me personally though. I don't care one way or the other; my TV only has one digital input, and my (preordered) PS3 has always been destined to occupy it, just as my 360 occupies the component in, and Wii will occupy the S-video in. Since HD movies are destined - by gentlemen's agreement between movie studios - to not require DRM across the video connection until 2012, surely my 360 will have been retired and replaced by a 960 or whatever by then, which HAS to feature a 'secure' video transmission link as standard...
Frankly, this is a bit of a non-issue, the 360's component video out looks great, but fact is, HDMI from day one would have been logical, and smart. It isn't expected of MS to act stupid like this... Most people only have one component-in on their TVs, but may have more pieces of equipment to plug into it; satellite tuners, DVRs, cable boxes or whatever. Offering HDMI in addition would give people more freedom when hooking their stuff together. I can imagine things a lot more fun than crawling around in the dust behind the TV, ripping out/replacing as many as five leads whenever I want to play a game on my 360, only to have to do it again when a good TV show comes on...