Exactly. I did tech support in college, and there's often a huge gulf between what people ask for and what they want. Especially with the rise of the web and apps, we've shifted plenty of power into the hands of users and customers already.
Voice-based systems currently combine all of the limitations of human conversation (e.g., low bandwidth, strongly linear, possibilities hidden) with all the limitations of computers (e.g., not very bright, highly literal, inflexible).
I think the main reason they're so popular for support is that people are bad at accounting. If I install an IVR system, I see that calls to human agents go down, saving me easily measured cash money. But I probably haven't measured the time and cognitive load burden shifted to customers, or the value lost by suboptimal use of whatever they're supporting.