​There comes a point in every failed coaching tenure when you have to ask the question: If not now, when? Lincoln Riley is squarely in the middle of that conversation. It is Year 5 at Southern Cal. He has been given everything he needs to win, from a massive contract to a well-funded roster to a palatial new football facility. He spent the offseason talking about having alignment with the administration and a roster capable of winning in the Big Ten. He hired his third defensive coordinator in Gary Patterson, who happens to be one of the greatest defensive minds in the history of the sport. He has an experienced quarterback in senior Jayden Maiava. And on Saturday, he had Oregon at home playing without its starting quarterback for the entire second half.And it still wasn’t enough.When’s it ever going to be enough for Riley at USC? Or, more to the point, when is USC going to say it’s had enough? The evidence is in. USC fans don’t need any more to render a verdict — and it is beyond a reasonable doubt.  This just hasn’t worked. USC’s 41-27 loss to Oregon on Saturday was a moment of clarity because it exposed that for all the talk about what’s different at USC, not much has really changed. Whether it’s Caleb Williams or Jayden Maiava playing quarterback for Riley, it’s the same product year after year after year. And it’s not good enough to win at the level Riley was hired to achieve. There will be plenty of time to dissect why it’s turned out this way and how both the Trojans and Riley can unwind themselves from this marriage. But when you knock out Oregon quarterback Dante Moore on a dirty hit and then celebrate it going to the sideline, as USC’s Desman Stephens did before he got tossed from the game, there should be no excuse or tolerance for allowing 28 second-half points and 289 passing yards to backup Dylan Raiola. It’s even worse, though, that nobody’s surprised. In fact, it’s almost expected at this point because USC’s big issues don’t change from year to year. They. Don’t. Play. Defense. It doesn’t matter if it’s Patterson or Alex Grinch or D’Anton Lynn, who have all had success elsewhere. You can even go back to Oklahoma, and it was the same problem. Season after season, Riley’s teams have a brand — and that brand is needing a Heisman Trophy-winning college quarterback like Baker Mayfield or Kyler Murray to score on darn near every possession. How do you win that way over the long haul? It doesn’t work. And the only common denominator is Riley. Lincoln Riley and the Trojans came up short against Oregon yet again on Saturday. (Kiyoshi Mio-Imagn Images)IMAGN IMAGES via Reuters Connect / REUTERSWhile it’s unreasonable to write off the season for a 4-1 team with this much talent, USC still has to play at Penn State, Wisconsin, Indiana and UCLA, with a home game against Ohio State. If the Trojans can get to the CFP for the first time under Riley with that schedule, we’ll do all the mea culpas. But the way they play football