We estimate that by 2025, Signal will require approximately $50 million dollars a year to operate—and this is very lean compared to other popular messaging apps that don’t respect your privacy.
Nothing gets lost. Not having every packet get delivered is already entirely normal on any internet application, and already solved.
Solving that “problem” is as simple as sending an acknowledgement back when a message is received, and retrying when acknowledgement isn’t received. Routing P2P is more (but not very) complicated than that is.