One needs to appreciate that TV had stars in the 70s. To be a Big Name, you had to be able to do period drama (Young Pioneers), sit-dramedy (Happy Days), charm on talk shows, sing on variety shows, dazzle on Circus of the Stars. The occasional Afterschool Special (or something that looked like one, like Having Babies or Black market Baby) wouldn't hurt either.
Linda's introduction to Happy Days was an attempt to get The Fonz into manhood as the girlfriend we thought might stick... if we had still cared about the show after 10 seasons. And lord knows we didn't. The line up that year, like Fonz, had hung around too long at the malt shoppe, and the younger siblings could not fill their origins' shoes: Little House New Beginning, Father Murphy, Joanie Loves Chachi, Archie Buncker's Place, Gloria (someone must have lost that in a bet), Benson, The New Odd Couple... oh make it stop. Square Pegs was on the scene Monday nights and something new was in the air.