Our email won't come back on premises as it was moved to O365. Also or file server. I've also replicated most of our servers to Azure. It is certainly not a perfect cloud but neither was our on-premises environment. There are advantages and disadvantages to everything. I don't expect us to ever move these services back on-premises, but can't say cloud is forever. Who knows what the next big thing in IT will be? What will be the replacement for cloud infrastructure in the future.
Will some type of AI environment replace what we have now? Or some other technology we can't envision be the next big thing? I can't say, but for now we have embraced (for some things) the cloud.