Why segregate use so distinctively? That's almost always been the recipe for urban decline. I'm fine with residential here.
Heck, while we're at it, why stop at 60? Why not 80 or 90?
Sounds so "urbanist", but if segregation were the recipe for urban decline, then Toronto would be a desert. Seriously, how many of Toronto's streets are actually mixed use? Like 8%? Are downtown streets like Jarvis, Beverly, Bay, Sherbourne, McCaul, Mutual, Huron, really "mixed use"? Are Rosedale/Moore Park mixed use? Is the entire so-called midtown outside Yonge st "mixed use"? North of Bloor st, how many of Toronto's street have a decent amount of non-residential buildings? like 2%?
If segregation were the recipe for urban decline as you dramatically concluded, then what would Toronto be? It is like the king of segregation city wide. You go to see Paris or Buenos Aires or Tokyo or Shanghai, those cities don't work like Toronto. They have shops everywhere. This has gotta be the first time I am considered "segregationist" as I deeply loathe pure residential areas, which happen to be one of Toronto's main characters.
You know why I don't think a 90s condo is not a great idea, because there will be too many people at that small intersection. Massey tower is 60s just across the street, isn't it? I never dislike "too many people" but unfortunately the sidewalk is not wide enough for all the 150 stories of residents AND workers AND shoppers/tourists. Unless the city make the bold and necessary move to make Yonge st downtown carfree, which will never happen because of our love of cars, where will those people even walk?
The building needs to be renovated, and probably a 20/30s tower may be reasonable, but a very tall condo won't make sense here. It is too small an intersection with too little space. There isn't even a grocery store nearby. And I am saying this as someone who has been frequently (and was wrongly blamed for blindly) advocating tall towers.
Toronto (including DT)'s problem has never been the lack of residential buildings on commercial streets. It is rather the lack of commercial buildings on residential streets. You got it totally backward.