Last time I checked, a good chunk of the old Canadian political establishment (and the electorate it reprsented) couldn't give a damn about our modern heritage
Well, I'm not sure if I'd be that blunt and negativistic in outlook; however, as I've also implied re the Regal Constellation, I think we're too often prone to jumping the gun re the "official" recognition (or lack thereof) of modern/recent past heritage--though yes, such gun-jumping might work in the long term in sending a strong message.
As I honestly see it, something of Bata's date, style, and function would have been scarcely less endangered anyplace else short of Columbus, Indiana--and even more emphatically so half a decade ago (when the Aga Khan deal was struck) than now. Up to that point, designating Bata would have been extraordinarily (if delightfully) precocious (and there's no guarantee that even Sonja Bata would have agreed to such a move). And it's not about philistinism; rather, it's the political reality of heritage, and the selling thereof, especially in our days of bureaucratic cutbacks and skimpy resources. After all, take it any further and you'd have a valid heritage argument on behalf of the Barton Myers/KPMB AGO, which was only a third of Bata's age when it was eviscerated on behalf of Gehry.
Really, the best way to preemptively address these kinds of issues, short of a Napoleonic "heritage until proven otherwise" policy, might be to institute 10/20/30-year lists of works of architectural significance as a feeder for our heritage inventories--maybe not a bad notion, come to think of it...
Oh, by the way, "Moderne" is a term more commonly identified with 30s Deco and streamlining than with the International Style.