Bringing an old thread back to life just to shed more light on this conversation, but Lindsay was bought by Proflex rubber in Quebec in ~2017 and they upgraded the lindsay puck to match it to NHL standard. They now produce under their own brand "Pro-flex" which is the puck found in semi-pro leagues (chl, ahl, junior, etc if I remember correctly). They also make the Sherwood puck for Canadian tire now. So now Pro-flex supplies a big part of the north american market of made in canada pucks, but more precisely in Canada.
Soucy still makes the NHL puck for InGlasCo in St-Jerome. All other inglasco pucks come from EU.
There are a couple other players that make canadian pucks but are lower volume and sometime switch from in-house to imported pucks.