Well, Calendar view is just a view. (a point of view of seeing task)
In RTM the view is vertical, one after other.
But whatever u can do with calendar, u can do it with this too. Additionally it allows labels too. (Similar to Gmail)
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My point is calendar is old concept based on diary, you always move to something better the concept of RTM is different. A single page serves many purpose.
Btw calendar is also TODO list isnt it?