Hate to tell you but before the PC9 there were the AERO, HiPoint.... in multiple calibers. I expect Ruger to come out with at least a PC10 and 45. To be competitive they need to have caliber conversion kits cheaply.
But Ruger does some development besides the revolver market, e.g. the RPR Interest in bull pup is growing and the market is fragmented allowing room for a couple different entry paths. Bolt actions in calibers like: 7mm08, 308, 300blk, .... Semi autos in rimmed calibers e.g. 38 Super, 357, 41, 44, 45 colt, 480Ruger, 460S&W, 45/70....
Whether any will happen is to be seen. Hopefully Ruger will float trial or two.