I think a lot of it has to do with Toronto's distinct lack of style / taste when it comes to art and architecture. Our elite class is about 10-15 years behind on trends (you can see this especially with custom home design, which is largely stuck in the Pinterest Joanna Gaines Dwell 2010 Modern Farmhouse White and Black look).
Many designers are still stuck in the cool minimal modern era while the rest of the world has moved on to more robust design trends that utilize materials like masonry, wood and coloured metal combined with references to the local vernacular.
It's been brought up before, but Toronto has a deeply conservative design culture. Fortunately we've got the Gairloch's / Slates who are able to push past this mentality.
Fear of being gauche, tacky or "too much" has an unfortunate grip on the tastemakers of the city. I'm hopeful that the new generation of firms can break through this unfortunate trend.