It's possible that both the hosting[1] of apps and also inter-app communication[2] would be possible via IPFS.
Orchestration of the resources (CPU, memory, storage) to run API services would also be possible in a distribution manner if we can envision something like Kubernetes to manage workload allocation across compute hardware (smartphones?) and if there's a way for participating nodes to obtain container images and storage volumes (IPFS / Tahoe-LAFS?).
Signing and trust would still be an issue, particularly for container images and storage volumes.
I don't see why it wouldn't be possible, there are already working websites on IPFS. I think we will see more as IPFS support in browsers increase. Opera launched native integration for IPFS weeks ago, hopefully Firefox and Chrome will follow at some point.
Orchestration of the resources (CPU, memory, storage) to run API services would also be possible in a distribution manner if we can envision something like Kubernetes to manage workload allocation across compute hardware (smartphones?) and if there's a way for participating nodes to obtain container images and storage volumes (IPFS / Tahoe-LAFS?).
Signing and trust would still be an issue, particularly for container images and storage volumes.
[1] - https://withblue.ink/2019/03/20/hugo-and-ipfs-how-this-blog-...
[2] - https://github.com/peer-base/peer-base