Not true. In fact, a case has been made for a long time for a more diversified transport fleet. The Herc is a tactical airlifter, and to use it (as the CAF has) for intra-theatre lift very quickly burns a whole lot of life out of the airframe. What is needed (and is ultimately being delivered) is an appropriate mix of heavy lift with outsize capability (the C17), passenger transport (the A310/CC150 as well as C17 when available), tactical transport (existing C130s or C130Js) and some sort of lighter utility aircraft for Search and Rescue and Northern Ops.
This mix will allow the Air force to do what is asked of it in the most efficient manner possible.