Bike lanes in Toronto have been around for a while now. The first was created around the 1970s: at St.Clair, then Wellesley.
It’s not as simple as you may think to create bike lanes. Right-of-way (one way or both way), amount of traffic, connecting to other bike lanes (and routes), parking spaces & needs, specific by-laws, money, neighbourhood feedback, and types of lane signs are considered in the making of one bike line. Imagine that for a whole city! Paints and specific torches have to be bought and shipped from another place as well – typically thermoplastic is used, as it is more durable than paint, and can last up to 10 years.
There is development going on for quieter streets, by using more bike lane markings for more bike traffic rather than car traffic.