There is also google sketch-up which, as I understand, is free and particuarly good for building modeling. In all seriousness Max sucks badly, and I dunno about maya. I think being able to use several different modeling programs would be beneficial. Unfortunately, I don't currently know much about model import pipelines, so I don't know the drawback to just using .obj files, which, as I understand, are pretty standardized.
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Well, Sketch Up doesnt sound very realistic by any standard, if only that it's not an animation package. I'd love to own Max or Maya, but virtually the only people online who actually *own* Max (not to be confused with the number of people who *use* it) are students that are required to purchase it (and receive a significant discount), and companies who buy it for their employee's use.
I'm sure Boogie can show up here and list any number of technical reasons this or that way, but I'm sure it's also largely just a matter of practicality. Like Brad has said a number of times, the early portion of development is mostly devoted to building the *tools* they then use to build the *game.* And since they use Max and Maya in the studio, they have to build tools to export from those to make the game. We'll probably get some version of those same tools, which have the benefit of being vetted and refined in a production environment, so they know pretty much how well they work.
From there it's just a matter of practicality, on whether or not it's worth taking any time away from developing all the other projects on the impossibly large list of things they want to do for the game , simply to cater to the lingering few people online who prefer to *own* their software legally. Sucks, but that's losing math every time.
Still, with as much as Brad was talking about how this was going to be an ambitious community mod-driven game, I had sort of hoped they might be able to suprise me. When Valve *really, really wanted* the community to mod their engine, they worked with Softimage to release a full fledged Lite version of XSI for free for the community to work with. Worked out pretty well for them. 
Speaking of which, i wonder if there would be any hope to write an exporter for the XSI Mod tool :
http://usa.autodesk.com/adsk/servlet/pc/item?id=13571257&siteID=123112
I suppose I'm jumping to conclusions here. Maybe they will surprise me yet.
