I don't think it ever caught on in Canada. I've don't recall ever hearing of anyone talking about Marmite. Neither grandparents or any ancestor stories, no talk of it.
Marmite is available in many grocery stores in here but commonly in the international foods aisle. My local store (rural Ontario) put in the baking section with the yeast. LOL
While certainly not a customary staple, it is commonly available here (and delicious). Marmite and PB on toast, yum.