I'm not entirely sure that having a "different" power generations would make it more effective, given that boxing actually was greatly refined for a long time due to boxing being continually practiced, tested, applied and succeeded in probably hundreds of thousands of sparring sessions and real matches (same goes for Muay Thai and Kickboxing - I wouldn't knock kickboxing, especially dutch kickboxing, solely because of the likes of Ramon Dekkers kicking ass in Thailand), although those three reasons you've mentioned may have accurately state the main reason why traditional gung fu had failed where other arts had dominated, particularly reason #3.
That's why San Shou, which tries to combine all that's effective in different kung fu styles into one, looks like kickboxing now.
But who knows? Maybe one day there's going to be a kung fu guy in MMA whom TMA can put their banner behind, akin to Lyoto Machida's shotokan karate. Now comes the challenge of separating the BS and finding what's effective, hoping that what's effective haven't already been discovered by the martial arts used in MMA now