Personally, I'd love to see software updated regularly, provided there's room for improvements/features in the code. For the majority of drivers though, and especially the press, I'd think that bringing the car in to the dealer for software updates would be perceived as fixing flawed code, and would probably generate negative vibes to an average consumer. More versions of software floating in the wild also makes troubleshooting more difficult as additional variables are introduced and the higher likelihood of bugged code slipping into new releases.
From a business perspective, today's car manufacturers now have a brand new angle to drive trade-ins to the newest car model, and that's software features. I could draw a comparison to 35mm cameras, which 10 years ago, once you bought one, it was pretty much a long term investment. Now with the age of digital cameras, we are on the upgrade merry-go-round with megapixel and software improvements driving camera upgrades every few years. In the same fashion, Toyota would not have an incentive to update software features on older cars (hardware permitting), when it could play that card to drive sales of the new model.
That said, as we move forward I think we'll start seeing more two-way data links (through XM for instance) for live traffic conditions, weather, and maintenance alerts; in fact I believe the Acura RL is already doing some of this. Once that door opens, I would believe it technically feasible to wirelessly transfer a new firmware image to the car while driving, with the ability to flash the system with the downloaded image at the next power cycle. Of course, security becomes a MAJOR consideration in that scenario as, to date, the communication systems (phone/audio) have been completely isolated from vehicle control systems. I think liability would play the largest role in this ever seeing the light of day. Hope it does though, but I'm a geek.
Great thread!