Despite a hefty budget, luxe visuals and a rotating cast of talented actors conspicuously better looking than their real-life counterparts, “The Crown” ends its six-season run on Netflix revealing surprisingly little beneath the royal family’s inscrutable facade. With the monarchy forever battling reputational damage off-screen, “The Crown’s” (mostly) deferential approach has been all the more puzzling. By design, biopics and their TV counterpoints must decide which details to include and which to leave out. Show creator Peter Morgan has made it clear certain things are off-limits. Though Prin…