Non power users would use this more if the docs, marketing and promotion of it was prominent and talked about (or made to look "sexy" for lack of a better word). I think what we're seeing is that the "UX" folk have hijacked the conversation and made it so that it is the only expression of the capabilities an app has for user interaction.

I'm sitting here, recalling all my chats and meetings and workshops with UX folk, and not once can I recall the topic of keyboard shortcuts or tab sequence being brought up. It was all about color, branding, spacing, user flow, "journeys", "experience", conversion funnels, and all things visual.