That fire pole costs a lot less than the salary increase you'd need in order to achieve the same level of employee retention. Google has quite a bit of engineering talent; you don't want that talent to evaporate for the sake of some short-term cost savings. Your scheme will absolutely affect innovation: it will cause innovators to leave.

If you want to cut datacenter costs, reward engineers for impact, and include cost savings under your definition of impact. Engineers are pretty rational people and will respond to incentives.