even as a Platinum you do not get regular op Upgrades
there are actually also few occasions!
as a Platinum you usually fly anyway Business as otherwise miles do not count for status and there are only few flights left, where they operate F, so very few occasions for upgrade
my last op upgrade was years ago, but what you get quite regularly is to sit in the F cabin where they operate 747 (and A340, 777 with F in the past) and do not sell F (just last week from Europe to BKK)