The one thing I think it is perhaps a little unfair to completely blame JR for is Gary and Valene leaving.
Not when Gary and Val were teenagers. Gary was running the ranch at that time. J.R. piled pressure upon pressure on Gary and Val, aiming to break Gary. Why? Because Gary was married and had a kid (and perhaps more on the way), and was a serious potential threat to J.R.'s ambitions. A potential threat is all it takes for J.R. to consider it a deadly threat, as he once said "Do unto others before they do unto you". And once Gary had broken down under the pressure and left Southfork, then Val was easy pickings for the same treatment. But while Val looked vulnerable on the surface, she got stronger with every setback in her life, and she snuck back for Lucy. J.R. sent a load of heavies after Val and ripped Lucy away from her. When a determined Val again refused to go away and took legal action, J.R. threatened to kill her if she ever returned to the state of Texas.
As for Jock's role in this at the time. He didn't like Gary just marrying somebody of Val's humble status just 3 days after meeting her and not telling the family for months afterwards, but while Jock (unlike J.R.) grew to like Val, he still piled the pressure on Gary to live up to all his responsibilities. J.R. though, was much worse.
Gary wasn't cut out for the business in the same way that Bobby and JR were
True, but is that bad? Gary was running the ranch, like Ray Krebbs was when the TV series starts. Gary was far less ruthless, had an interest in different hobbies and subjects (animal welfare, environmentalism, poetry, painting etc.) that his father and brothers had no interest in, but he was stubborn and insisted on doing things his way. Gary would also run away when under pressure rather than stand and fight. This unnerved J.R. greatly. Gary did not play by the Ewing rules. Bobby, in contrast, did play by the Ewing rules, and J.R. embraced his rivalry with Bobby.
Just remember that Dallas episode when J.R. thought that Gary and Val were coming back to live at Southfork after Gary and Val had gotten married again, and was looking very worried. When Sue Ellen then told J.R. that Gary and Val were moving to live in California, J.R. was laughing. Ask yourself why J.R. was nervous and worried about Gary and Val being around Southfork, but thought it funny that they would be living in California?
and while JR probably didn't want him around, I think it worked out it everyone's interests - Gary and Valene's included - that they headed off elsewhere.
Yes, away from J.R., but in those early seasons of Knots Landing Gary was often feeling frustrated and even bored with his lifestyle of working his job at Knots Landing Motors and Val treating him like a china doll as she was scared that he would go off the rails. I think Gary's relationship with Abby helped him embrace responsibility more. Abby had a bit of J.R. in her, but was interested in helping Gary reach his potential by pushing him to greater heights. Abby refused to give Gary the comfort blanket and security that Val gave him. In the long run, it did help everyone. Ironically, I'd say Gary was stronger than both J.R. and Bobby by the late 1980s and early 1990s, even though he still had his faults like gambling away nearly all his fortune on a Tidal Energy scheme.
