I think it might be a bit disingenuous to say that, prior to the Warwick, Winnipeg's apartments were simply working class tenements. There were a number of apartment buildings that were built as fine residences for middle and upper classes in the years before 1909. The Warwick, and the Roslyn, which also opened in '09, were simply a new benchmark in desirable apartments.
The Royal Alexandra Hotel was easily the nicest hotel in the city when it opened in 1906, but that doesn't mean that the previous generation of nice hotels (the Leland, the Empire, the Manitoba, etc.) were built as dumps for a lower class of guests; they were simply built for a smaller, less prosperous, and less modern city.
Even in the 1880s, multi-family residential developments--usually townhouses--were very popular among prominent and wealthy citizens with small families. Most of these had fallen out of fashion by 1909, and could very well have been described as working class tenements, but they certainly were not built that way originally.