It isn't just me that has been hoping the LC would have related items like mix, ice, etc. which you commonly use with alcohol to better make it a one stop shop. You might not need 50,000 to pull it off but it is worth noting the 15,000 sq ft flagship at Grant Park does not have the bottle and cork wine section or the expanded product offerings. Those would need extra space. If they planned to expand their class based offerings that too would bump space up.
I honestly believe there was more of a plan in place than is being portrayed by the media but it might have lacked a detailed cost-benefit analysis to determine that it would make money.
Edit: As a point of reference though, a large US multi-location alcohol retailer lists their largest store as being 12,000 sq ft putting it in line with the Grant Park store.
Wine and Beyond in Edmonton seems to be western Canada's largest at 20,000 sq ft,
LCBO seems to have a 31,000 sq ft store and
DaveCo in Denver holds the Guinness World Record as the largest liquor store at just over 100,000 sq ft.