Inside AT&T (but outside research) there was considerable pressure to use AT&T products (3B, System V, BLIT/5620, Datakit) rather than the externally developing Sun/Ethernet/TCP suite, especially in the mid-late 1980s. We all (mostly) hated them and wanted Suns, but we were told "eat your own dog food."
The 3B20 and 3B5 were awful, but the 3B2 had potential.
Once we got a working TCP/IP network in Bell Labs the tide turned in favor of Suns