My travel patterns fortunately have me avoiding peak days and times generally so not sure how helpful this will be, but I've missed 2 upgrades out of 30 sectors (that were either <500 mi or on which I used stickers to request an upgrade) this year as a Plat.
This includes flying into and out of DCA as my home airport and several shuttle flights. I typically book 2-3 months in advance and was among the top 5 on the waitlist on those 2 sectors I didn't clear. And of course, I avoid DFW like the plague.