I've been wanting a computing model I call PAO [1] for a long time. PAO would run personal application "servers" and connect dynamic clients across all devices. PAO is centralized, but centralized per user, and operating at their discretion. It avoids synchronization, complex concurrent data structures, and many other problems associated with alternatives. Its weakness is a need for always-on networks, but that complication seems ever easier to accept as omnipresent networks become realistic.

[1] https://tiamat.tsotech.com/pao (2012)