My bad. I saw signs at Don Valley station showing the station is open 24 hours. I presumed it was like the subway: when it's not running at night, the stations close, including surface vehicle platforms. (I could be wrong about that too, maybe some stations remain open at night, but none that I've seen.)
When I was a kid, I lived next to a streetcar line which ran day and night. Also when I was a kid, most of the TV and radio stations went off the air at night. There was almost no traffic on the roads after midnight. Restaurants like McDonalds did not stay open all night. Services were minimal because almost nobody stayed up at night. As urban areas grow, all that changes. Many more people have night jobs now, or have flexible hours, and they are up at night, including on their days off. I remember when the "blue night" service came in, which was a great idea, and I expected 24 hour service on the subway to be the next step. Many night buses run half an hour apart; I see no reason why the subway and LRTs can't do the same.