We aren't in a developing country though. In 5 years we'll be at 2 million people, in 10 we'll be at 2.5 million. In Canada. That means every one of those 2.5 million people have spending power, entitlement to high quality Healthcare and education, the opportunity to start a business in the formal economy, developed world housing requirements, expectations of eating out, traveling, shopping, and make up a large media market.
And? It's not like people don't know cities in developing countries. Phnom Penh has about 2.5 million people today and regardless of how little spending power the average Cambodian has to the average Canadian, it's still a revered and known place. My point is that size isn't everything. Edmonton can potentially be more prominent, at least domestically, though. I'm less sure about internationally, just because of how much Calgary casts a shadow and I don't know if the genie can be put back in the bottle on that one. Keep in mind that other cities are growing too -- Edmonton may reach Austin or Denver's size, but by then they'll likely be Minneapolis and Detroit sized. There was a time when having a million people constituted being a big, bustling metropolis, but the standard continues to march upwards. And then there are places like Cleveland that are relatively stagnant but carry the historical weight that Edmonton will never have.