I think the clip doesn't necessarily exhibit a brighter perspective but more of a desire to enjoy a comfortable life, something moviegoers aren't able to. The scene is set in England, everyone is elegantly dressed and enjoying a live show the appears beyond vaudeville. The movie goer may be envious Ziegfeld can toss a fiver or to wish they were the doorman.
Themes in future musicals: lighthearted, playful songs staged for an audience. Seems like to show an audience is trying to get the movie goer to become part of it. Ambition of the actress/actor; the vying for the better deal and lo