The hotels in Calgary are also being driven by having actual business travellers, it is not solely relying on tourism. For example, next week is the annual O&G conference, and nearly all Calgary hotels are full at HUGE rates. Many hotels who have corporate rates with business clients have blackout rate periods for the conference and Stampede. In addition, Stampede is not fully driven by tourism, but also tons of business travellers who come annually from Canada and internationally.
As mentioned by others, it doesn't make sense to compare ourselves to Calgary in this regard, they have lapped us and we will never catch up due to our city not being a real business city and overly reliant on government jobs. Edmonton could easily support another ~4 star property like a JW, Germaine, Fairmont and another smaller hip hotel like an Alt (both in the DT core).