Still.Me wrote:

Where did they all go?

They're not CRC-compliant (CRC is "child-resistant container), so they can't be sold in Canada anymore. Yes, they can be CRC-compliant, but even Canadian outfits like QP don't seem to be interested in trying. There's not a lot to it - all they need is a spillproof fill hole and a deck that takes two actions (like push or pull and twist) to remove. It isn't rocket surgery or anything, anyone with even the slightest modicum of engineering ability could pull it off without a hitch, adding one injection-moulded part (for the fill port) and about forty seconds to the CNC cycle time for each of two parts in machining for the deck mechanism.

That said, there's no restriction on importing personal purchases, just selling to Canadians in Canada (you'll note that outfits like Vapes by Enushi, who have a sizable international clientelle, still have RTAs/RDAs/RBAs on their site for international purchase).