A more successful example of open standards would be the various standards that browsers use. Would you say that browser innovation has slowed down? The model adopted there is less "Wait for everyone to adopt this new standard we wrote" and more "If you have a feature you found many people are using, suggest it as a standard and we'll get all browsers to implement it".
This model could be replicated to messaging solutions as well, without slowing down any innovation as companies can add new features, as long as they get standardized over time.