First off, it's probably 15 million CAD... which is... not far off of the USD, but still, that little difference makes a huge difference 15 million times later.
Second off, this is fucking Whistler. It's goddamned one of the most expensive places to live in Canada, if not the entire goddamned continent. This isn't even remotely the most expensive house in the land. A house like that is pretty damn big in Whistler.
Lastly, where's that 11.5k sqft house located? If it's in Texas or Nevada or some bullshit flat/hot place nobody wants to really live in, then it doesn't count.