I'm pushing 450k LP's and I haven't missed an upgrade all year. I've either cleared at T-100 or been #1 on the list and cleared at the airport.
My trick is if I have to connect in EXP heavy airports like DFW, CLT, PHL or MIA, I just buy F or J outright. If I'm flying non stop to any other airport, I just buy Y and play upgrade roulette if F/J looks empty enough (C7). I think a lot of travelers were doing the same, just buying F/J outright.
Prices are through the roof now, so that practice may change.