I, too, am enjoying The Virginian reruns on the Encore Western channel. Steve left because as Gary Clarke now admits he got into his head that he was much better on his own than as part of the ensemble of the show. He got an offer to star in another Western and jumped at the chance. Everyone from Drury to the execs of the show tried to caution him that it was a mistake but his ego wouldn't allow him to hear them. They wrote Steve out by having a US Marshal offer him a job. It was the episode where Steve reconnected with a childhood girl friend who was now working the wrong side of the law and her real true love was the head of a gang of robbers. Steve was deputized to infiltrate the gang and get the goods on them. At the end of the episode, the Marshal (played by Don Collier who would go onto the High Chaparral, offered Steve the job permanently.
Betsy, as you noted, met a young minister in an upcoming episode. The Judge's niece, Jennifer, came to Shiloh shortly thereafter. I think it was explained why the Judge ultimately leaves and that episode should be in the next month. After that, John Dehner took over as Morgan Starr (There's a whole episode devoted to his arrival). I don't think it was explained why Starr left Shiloh but John Grainger (Charles Bickford) then arrived. His grandchildrenm Stacey (Don Quine) and Elizabeth, came to Shiloh as well
After Bickford's untimely death, I think the show explained why Clay Grainger (John McIntire) came to own Shiloh. Stacey and Elizabeth, stayed on. Soon afterwards,Clay's wife, Holly (Jeanette Nolan, McIntire's real-life wife) arrives.
They stayed with the show until it went a complete make-over and becomes The Men of Shiloh. I don't know if it was explained why the Graingers and Elizabeth leave and the owner, Alan MacKenzie, played by the actor Stewart Granger takes over.
I don't know if it was explained why Randy left but Randy Boone stayed through the Morgan Starr ownership which was at least a season and a half after Betsy left.
I also don't know if they explained why Ryker ultimately left.
Lynn in Sherman Oaks
"Film is history. With every foot of film lost, we lose a link to our culture, to the world around us, to each other and to ourselves."
"For me, John Wayne has only become more impressive over time." Marty Scorsese
Avatar-Bob's Big Boy-Toluca Lake, designed in 1948 by Wayne McAllister, still in business.