But, further, I'd argue that this whole presentation of the domestic space was nothing new. The 'public' sitting room was a heavily theatricalized space long before Burns & Allen. Unlike earlier phases of drama, the Victorian parlor comedies (think of Oscar Wilde) and domestic tragedies reflected (and perhaps inflected) the idea of the sitting room as a space of public performance. Sitting rooms were the natural venue for interpersonal strife and for staged scenes. Not least because the sort of performance that'd we'd see represented on the stage in those spaces was already intimately familiar.
I turn to personal experience. I grew up with the closest thing a child of the '80s could experience to a Victorian stage sitting room. My grandmother was a bit of a throwback to an Edwardian theatrical tradition. She'd grown up in the classical theaters in Dublin, Ireland, in the '20s and '30s. She never turned her theatrical instincts off. Her sitting room was very much a stage. It was the site of real life theatricals: either cocktail parties and receptions where she would stage-manage gossipy conflict among her guests or literal spectacles when she would mount readings of Victorian parlor poetry.
Strikingly, the geography of her sitting room looked a great deal like the ersatz living space George Burns steps into across the double proscenium (both the one upstage and the one left by the removal of the fourth wall of his living room). Her sitting room, like "his," was a stage. But it was also just a sitting room. There was no discontinuity between those functions because we ourselves were intended to be participants in the on-going drama of her devising. And the contrary is also true: George and Gracie's sitting room looks pretty much just like a sitting room because we know that public sitting rooms are stage spaces. At either angle, intimate life was the site of drama because drama was already at home in intimate life.
As Spigel points out, camera work gives the television audience a degree of intimacy with the drama that theatrical representation cannot muster, but it strikes me that that intimacy is merely an extension, and not a reversal, of the logic of the theatrical tradition from which the shows draw. By staging their scenes in the sitting room, the Victorian and Edwardian traditions were already reaching for the sort of effect Spigel attributes to television. We were invited to be intimate with the drama because the drama was supposed to be intimately familiar. The "illusion of presence" was already hard at work.