Their customers will attempt to build moats by creating improvements in sidechains, and those moats would be threatened by having that capability in Bitcoin.
If their revenue comes from having customers, they have an incentive to take actions that benefit their customers, such as using their influence to delay or block progress in Bitcoin.
It seems highly improbable to me that they would build for their clients anything that would be related to the monetary functions of Bitcoin. That's not what "building on top of Bitcoin" means. Applications do not correct or improve features of the protocol they run on. They model it to their need.
Also, remember that we are dealing with open source here.