Yes, but what interpersonal dynamics would have resulted from that?
David Jacobs resisted the suggestions of Ted Shackelford and Joan Van Ark during Season 2 that Gary would obviously have an affair with Abby. Jacobs felt that Gary and Valene were the main couple on Knots Landing. I gather from this that, had Jacobs stuck to this in the years following, that they would be more "normal" (including the down sides), and from a soap perspective "less interesting" and "small time".
Hard to say in a more detailed manner. There's a chance that Knots Landing gets cancelled after 4-5 seasons.