Wasn't Siri bought from another company which was already competing against similar products like Vlingo? Saying Apple pioneered it is a bit of a stretch. Especially considering how effective Android's voice commands were well before Siri was introduced.
1 - replaced what they already had and then moved it up to feature parity with the competitors
2 - pioneered it then let it sit, is Siri really that much better and personally assisting me today then at launch?
3 - which appears to be only a response to the competition's great cloud integration
perhaps stagnation is too strong a word... tread-milling perhaps?