That particular McDonald's was ruined mostly because a shelter and various other supports opened up down the block, and kind of turned the area into a mini-Skid Row. Victoria has the best year-round weather in the country: it tends to attract people who are living on the street, and there's big intersections there between that group and the mentally unwell, anti-social, and/or drug addicted.
As for why the mentally unwell, anti-social, and/or drug addicted have become a bigger problem in recent years, well, take your pick: laxer drug laws and/or enforcement, laxer enforcement of laws in general, safe injection sites, housing crisis, cost-of-living crisis, Fent and/or "super meth", cuts to mental health care programs, lack of God, you name it.