Aidin Vaziri | Nearly two hours into the Rolling Stones concert at Oakland’s Oracle Arena on Sunday night, Mick Jagger had already peeled off two layers of shiny tops to reveal a sheer black long-sleeved shirt that did little to conceal his sweaty nipples. He strutted expertly at the front of the stage – mouth agape, brows furrowed and arms flailing wildly as if he were trying to shake water off his skinny fingers. While the guitarists Keith Richards, Ronnie Wood and guest Mick Taylor dug into the well-worn crevices of “Midnight Rambler,” the singer headed for the walkway that looped around the arena’s halfcourt mark and literally started skipping. “Oh, yeah,” Jagger chanted. He turns 70 in two months.Some have suggested ticket sales for the Stones’ 50 & Counting tour, which continues Wednesday at San Jose’s HP Pavilion, were sluggish because of the exorbitant price tag (about $170 to $635 for a decent seat). It’s more likely that the band has simply outlived a large swath of its fans.