We ran an entire distributed multi-building school campus on AppleTalk, with multiple labs, shared printers in every building, and at least one networked staff computer in every classroom.
We absolutely handled more than two workstations using a shared printer without issue.
OpenTransport was a lot more stable than MacTCP, but that was just the TCP/IP stack. I have no idea what you mean by AppleTalk not being available on PPCs; it absolutely was, and it wasn’t replaced by OT.