Being within walking distance of any and all manner of amenities, including the best bars and restaurants in the entire prairie region. Immigration may be down/offline but that wasn't the only key driver of downtown growth. People are always having kids, and kids will always be growing up, leaving home, and some of them - a lot more than ever before - are choosing downtown, because it's by far the most interesting place to live in the city.
A rise in vacancy rates is fine. It's wild that it took this long, and a rise doesn't mean that construction will be stopped.